Microformats Wiki - User contributions [en]

User:EtanWexler

2008-09-29T00:47:01Z

EtanWexler: cc-pd-license

= Etan Wexler =
<span class="vcard"><span class="fn n"><span class="given-name">Etan</span> <span class="family-name">Wexler</span></span></span> is <span class="vcard"><span class="fn n"><span class="given-name">איתן</span> <span class="family-name">וקסלר</span></span></span>. Yes, there exists a person who has two names, of which one is his official name in a certain jurisdiction of law while the other name is his official name in a certain and separate legal jurisdiction.

== declaration of public domain ==
{{cc-pd-license}}

User:EtanWexler

2008-09-29T00:32:03Z

EtanWexler:

rel-tag-issues

2007-11-01T03:38:28Z

EtanWexler: Corrected and unlinked example URLs

= relTag Issues =

These are externally raised issues about [[rel-tag]] with broadly varying degrees of merit. Thus some issues are REJECTED for a number of obvious reasons (but still documented here in case they are re-raised), and others contain longer discussions. Some issues may be ACCEPTED and perhaps cause changes or improved explanations in the spec. Submitted issues may (and probably will) be edited and rewritten for better terseness, clarity, calmness, rationality, and as neutral a point of view as possible. Write your issues well. — [http://tantek.com/log/ Tantek]

== Issues ==

Please use this format:
* {{OpenIssue}} YYYY-MM-DD raised by AUTHORNAME
*# ''Issue 1: Here is the first issue I have.''
*# ''Issue 2: Here is the second issue I have.''

* {{OpenIssue}} 2007-03-28 raised by [[User:JamesCraig|James Craig]]
*# [[internationalization|Internationalization]] (i18n) issue with restful tag spaces. Restful tag spaces cannot be used with non-western characters unless escaped in unicode, which renders a restful tag space quite pointless. For example:
*#*A Japanese Katakana tag ピフ would have to be <nowiki>http://example.com/tags/%E3%83%94%E3%83%95/</nowiki>
*#*A Hindi Devanagri tag चट would have to be <nowiki>http://example.com/tags/%E0%A4%9A%E0%A4%9F/</nowiki>
::There should be another way to specify the human-readable tagname.

* {{OpenIssue}} 2007-01-10 raised by [[User:AndyMabbett|Andy Mabbett]]
*# I recently received an e-mail circular, asking that images and blog posts about a particular event be tagged in the style:

::20070110 AB123YZ postcode:uk=AB123YZ upcoming:id=123456 upcoming:event=19876 upcoming:venue=14567 url=example.com geocoded geotagged geo:lat=52.3456 geo:lon=-1.2345

:Is any work being done, to document such tag "schema"? [[User:AndyMabbett|Andy Mabbett]] 12:43, 10 Jan 2007 (PST)

* {{OpenIssue}} 2005-06-21 raised by Hixie
*# ''Issue H-1: This specification is lacking a user agent conformance section. Does the UA simply crawl the DOM looking for all <html:a> elements with a "rel" attribute that contains a "tag" keyword (after space-separated splitting) and then grab the href="" value? How about relative links? Must they implement xml:base? <html:base>? Other things?
*# ''Issue H-2: What's the point? Isn't free-text search more effective than relying on people to remember to put a particular tag?

* 2006-01-10 raised by Adam Willard
*# ''Issue 1: Somewhat confused. Please either fix or elaborate the difference in the URLs in the Tag Spaces area -> is it /tag/ or /tags/ or /wiki/. Is this URI changeable or is this just showing other implementations. If this is the case I am confused on the implementation. Should /wiki/ only show tagged content of wiki? Should URIs be constructed as /definition/ /blog/ etc... to return those items? Or is it just returning pages and the webmaster just decided on /wiki/ or /tag/ or /applicationdir/?''
*#* ACCEPTED FAQ - We need to make this an FAQ entry. --[[User:RyanKing|RyanKing]] 14:46, 25 Jan 2006 (PST) (@TODO)
*# ''Issue 2: More information on actually implementing a tag space would be helpful. I wrote a tagging system on our intranet and we run IIS. So I had to install URLrewrite (ISAPI) to create the URI /tag/tagname. We horrible Microsoft people aren't as lucky to have Mod Rewrite.''
*#* REJECTED IRRELEVANT - Implementing a tagspace is well outside the bounds of the rel-tag specification. --[[User:RyanKing|RyanKing]] 14:46, 25 Jan 2006 (PST)

* 2006-02-09 raised by JonathanFeinberg
*# ''Issue 1: It's bizarre to have the tag be denoted by the URL. The content of the '''a''' tag is a perfectly suitable place to '''contain''' the tag.''
*#* REJECTED, IGNORES ESTABLISHED PRACTICE. Flickr and del.icio.us and other tagging sites established the defacto standard of having the tag term be denoted by the last segment in the URL. [[rel-tag]] was designed to leverage that existing behavior. Theoretical arguments about suitability are irrelevant in the fact of overwhelming existing practice.
*# ''Issue 2: There's no way to distinguish between an individual user's notion of a tag and a global tag (i.e., Fred's java tag versus all things tagged with java.''
*#* REJECTED UNTRUE. ACCEPTED FAQ. Tag spaces (see [[rel-tag]] specification) are used for distinguishing, e.g. Flickr does this with photos from one user with a tag, vs. photos from all users with a tag. [[to-do]] - add this to the the [[rel-tag-faq]].
*# ''Issue 3: It's not reasonable to restrict the host's REST implementation according to this spec's rather limited idea of a "good" tag URL. The idea of tags as query parameters is rejected without justification, for example. Query parameters are a perfectly legitimate means of denoting state.''
*#* REJECTED, IGNORES ESTABLISHED PRACTICE. Flickr and del.icio.us and other tagging sites established the defacto standard of having the tag term be denoted by the last segment in the URL and thus defined what makes a "good" tag URL. [[rel-tag]] has codified this good practice.

* 2006-02-09 raised by Robert Yates
*# ''Issue 1: So I work alongside Jonathan at Lotus / IBM and we have several systems in development each with their own tag implementations. All of them have their own pages that are dedicated to listing the things within them that have been tagged by a given tag. Some of these systems use a url notation that ends in /tag but many (the majority) do not. We are looking to have a standard way that these systems can sematically tag their tags and relTag looked very promising. However, given that some of the systems produce tag urls that do not end in /tag we are a little stuck. It would be extremely hard and somewhat impracticle to get all these groups to ensure that their tag urls end in /tag. Are you at all considering another approach. We'd love to use relTag within our products, but at the moment we can't. Looking for some help / guidance.''
*#* Clarification: By '/tag' do you mean '/<tag-name>'? --[[User:RyanKing|RyanKing]] 15:21, 9 Feb 2006 (PST)
*#*:* yes -- rob yates 18:56, 9 Feb 2006 (EST)
*#* I wanted to do a quick survey to see how many other sites would struggle to easily adopt this format, due to the fact that they don't currently end their tag urls '/<tag-name>'. While I definately agree that ending with '/<tag-name>' is a best practice, I do feel that their needs to be an option for sites that don't do this, but still want to semantically tag their tags. Here's some sites that I found that cannot easily adopt reltag without reworking server side logic. There's some pretty big names on this list.
*#*:* O'Reilly.com. See the tags at this url http://www.xml.com/pub/a/2004/11/10/delicious.html
*#*:* Dodgeball. http://boston.dodgeball.com/tags.php
*#*:* Any typepad blog. See for instance the categories here http://ideasinfood.typepad.com/ideas_in_food/
*#*:* Eventful. http://eventful.com/
*#*:* WordPress blogs, default permalink structure (http://example.com/?cat=N). Pretty permalinks (http://example.com/category/<tagname>) are supported through various methods, but cannot be enabled by default due to technical variances in web servers and setups. The rigidity of the spec has set a high technical barrier to entry. Even if the category name were put into the URL, it would have to be in the querystring for default WordPress setups, which isn't supported in the spec. A querystring fallback (?tag=<tagname>) would enable many more systems to use rel-tag. --[[User:MarkJaquith|MarkJaquith]] 15:39, 20 Oct 2006 (PDT)

* {{OpenIssue}} 2006-04-06 raised by [[User:Evan|Evan]]
*# ''The scope says 'rel="tag" is specifically designed for "tagging" content, typically web pages (or portions thereof, like blog posts).', but it's not clear how to associate a tag with one portion of a web page and not another. Some common use cases: image galleries, blog posts, yellow-pages directories, hcard directories, del.icio.us-style lists of bookmarks. Does the tag apply to the <a> element's immediate containing element? All containing elements? One possibility I suggest: the tag applies to the '''most immediately enclosing element with an "id" attribute''' (addressable, at least in XHTML, as #idval), or to the entire page if there is no such element. Another possibility is having a '''tagtarget''' class, so that the parent with that class is the object being tagged.''

* {{OpenIssue}} 2006-11-24 raised by [[User:AndyMabbett|Andy Mabbett]]
*# Why not ''also'' allow tagging on within-page links (i.e. after "#" as well as after "/")? Then, if I have a page with sub-sections, each of those could be a tag, according to their ID:

<pre><nowiki>
<ul class="navbar">
<li><a href="#whisky" rel="tag">Whisky</a></li>
<li><a href="#wine" rel="tag">Wine</a></li>
</ul>
[...]
<h2 id="whisky">"Whisky</h2>
[...]
<h2 id="wine">"Wine</h2>
[...]
</nowiki></pre>

* {{OpenIssue}} 2006-11-25 raised by [[User:AndyMabbett|Andy Mabbett]]
*#Caution should be advised when recommending Wikipedia as a name-space. For example, an article about Birmingham, Alabama, tagged with a link to http://en.wikipedia.org/wiki/Birmingham would link to an article about Birmingham, England. Similarly, a tag using http://wikitravel.org/en/Newcastle will link to a disambiguation page.

* {{OpenIssue}} 2006-11-26 raised by [[User:AndyMabbett|Andy Mabbett]]
*#There is a danger of encouraging users to breach [http://www.w3.org/TR/WCAG10/wai-pageauth.html#tech-meaningful-links WCAG 1.0 priority 2 guideline 13.6] "'''Clearly identify the target of each link'''". If a page has a link thus <code><a href="http://www.bbc.co.uk">BBC</a></code>, tagging it with a link thus <code><a href="http://www.example.com/BBC" rel="tag">BBC</a></code> will result in two links on the page, both labelled "BBC", with different targets.

*{{OpenIssue}} 2007-01-01 raised Jan 2006 by Ben Buchanan as [http://weblog.200ok.com.au/2006/01/limitations-of-rel-microformat.html limitations of rel="tag" microformat]
*#Summary: Under the current draft, tags and relevant tagspaces are potentially hard to create; and it's still easy to abuse the system. Humans can still be tricked and so can the machines. It's a great spec if you happen to have a compliant directory structure, but if your site doesn't match then you either recreate your entire system... or, more likely, you sadly advise the client that tags aren't happening.

* {{OpenIssue}} 2007-02-03 raised by [[User:Evan|Evan]]
*#There may be value in adopting, supporting or commenting on the [http://www.flickr.com/groups/api/discuss/72157594497877875/ machine tags] format in use at [http://flickr.com/ Flickr]. Machine tags (also called [http://geobloggers.com/archives/2007/01/24/offtopic-ish-flickr-ramps-up-triple-tag-support/ triple tags]) are a structured tag format with the syntax "''namespace'':''property''=''value''". Examples: "geo:city=Portland". It's not clear how machine tags interact with other microformats ("geo:long=..." and "geo:lat=..." are two commonly-used examples, which clearly overlaps with [[geo]]), whether other sites and services will support machine tags, and how to include them here.

== Need reformatting ==

These issues were mistakenly added to the [[rel-tag-faq]] and should have been put here in the first place. They need to be reformatted as issues.

===Are tags case sensitive?===
*Are tags case sensitive? Is "Dog" the same tag as "dog" and "DOG"?

===Multi-word tags===
*How should a multi-word tag be made? For instance, if using Wikipedia as a name space, a page about a Black Redstart (a bird) would be tagged '''Black_Redstart''', with an underscore [http://en.wikipedia.org/wiki/Black_Redstart]. Is there any way of aliasing alternatives ("BlackRedstart", "Black-Redstart", etc.)? Is any particular format preferable?

==Related pages==
{{rel-tag-related-pages}}

rel-tag-faq

2007-04-14T12:07:14Z

EtanWexler: /* Tags with file extensions */

= rel-tag frequently asked questions =

This document serves to answer and discuss frequently asked questions specifically about the [[rel-tag]] microformat. You may want to read the [[rel-faq]] first as it answers many common questions about the HTML4 "rel" and "rev" attributes, and their linktype values. If you have a new question to ask, first consider asking on the [http://microformats.org/mailman/listinfo/microformats-discuss/ microformats-discuss list].

== Q&A ==

# ''Where does a tagging link belong? Does the tagging link only need to appear in my Web feed (RSS / Atom)? Does the tagging link need to appear on the page where my specific blog entry lies? Does the tagging link need to appear everywhere that I can possibly imagine?''
#* In short, tagging links belong in all the places and formats in which you published tagged content. The Web page is the primary location where users read content and where search engines index. Thus the Web page is a place where you should absolutely include your [[rel-tag]] links. To tag your blog posts, put the [[rel-tag]] links inside them, visibly. The Web feeds are simply alternate ways of publishing your blog posts, and thus should include the full content of your blog posts, [[rel-tag]] links intact.
# ''Where shouldn't I use rel-tag?''
#* rel-tag expresses a particular relationship (a) between the page you are on and (b) the target of a link. If you're not asserting this relationship, don't use rel-tag. In particular:
#** don't use rel-tag in [http://en.wikipedia.org/wiki/Tag_cloud Tag Clouds]
#** don't use rel-tag to refer to the pages http://www.technorati.com/tag/xyz, http://del.icio.us/tag/xyz, http://www.flickr.com/photos/tags/xyz/ (and so forth) if you're not asserting "this page is tagged 'xyz'"
# ''The format specifies that the tag must "come after the last / in the path". Will something like <code><nowiki>http://example.com/index.php/TAG</nowiki></code> work? Or does it have to be a "real" directory or [http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html mod_rewrite]? -- [[User:Singpolyma|singpolyma]] 23:51, 24 Jan 2006 (PST)''
#* The key is the URL. Whether that URL is generated from a database or a directory does not matter. The URL matters.
#** My question, however, was about whether that URL form ( <code><nowiki>http://example.com/index.php/TAG</nowiki></code> ) would be valid, since there is the dot in "index.php".
#*** Yes, the URL in the example is valid (or legal or conformant or whatever you want to call it to minimize confusion). The dot (period, full stop, U+002E) is free to appear in most places in a URL, even in the middle of a path-segment that is not the last path-segment. (The latest specification for URLs, "[http://gbiv.com/protocols/uri/rfc/rfc3986.html Uniform Resource Identifier (URI): Generic Syntax]", is RFC 3986.)
# ''I'm developing a web application which uses tagging, and so of course I want to use [[rel-tag]]. For this application, I want nice, clean URLs. I was planning to use [http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html mod_rewrite] to map a clean URL onto my underlying scripts. How do I use Apache's [http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html mod_rewrite] to map <code><nowiki>http://example.org/~user/app/tag/car</nowiki></code> to <code><nowiki>http://example.org/~user/app/script.php?tag=car</nowiki></code> ?''
#* One solution involves changing the script to inspect the path for the tag (via the variable "PATH_INFO"), rather than inspecting the query:
<pre><nowiki><Directory "/home/user/public_html/app/>
RewriteEngine On
RewriteRule ^tag/([^/]+)$ script.php/$1 [last]
</Directory></nowiki></pre>
#* For people who can edit the server's main configuration file, the following untested configuration code may work. Corrections are welcome.
<pre><nowiki>RewriteEngine On
RewriteMap tag int:escape
RewriteRule ^/~user/app/tag/([^/]+)$ /~user/app/script.php?tag=${tag:$1} [last]</nowiki></pre>
#* The following configuration code, left over from a previous contribution to this document, does a poor job according to tests. The following code fails to enforce the [[rel-tag]] rules about the tag corresponding to the last non-empty path-segment. The following code fails to transcode the tag for safe use in the URL query. Consider that a request on <code><nowiki>http://example.org/~user/app/tag/</nowiki></code> would map internally to a request on <code><nowiki>http://example.org/~user/app/script.php?tag=</nowiki></code> . Consider that a request on <code><nowiki>http://example.org/~user/app/tag/not-a-tag/the-tag</nowiki></code> would map internally to a request on <code><nowiki>http://example.org/~user/app/script.php?tag=not-a-tag/the-tag</nowiki></code> . Consider that a request on <code><nowiki>http://example.org/~user/app/tag/the-tag/</nowiki></code> would map internally to a request on <code><nowiki>http://example.org/~user/app/script.php?tag=the-tag/</nowiki></code> . Consider that a request on <code><nowiki>http://example.org/~user/app/tag/attack&intent=destroy</nowiki></code> would map internally to a request on <code><nowiki>http://example.org/~user/app/script.php?tag=attack&intent=destroy</nowiki></code> .
<pre><nowiki><Directory "/home/user/public_html/app/>
RewriteEngine On
RewriteRule ^tag/(.*)$ script.php?tag=$1
</Directory></nowiki></pre>
<ol start="4">
<li>''Does a rel tag still have meaning if the link redirects? If the HTTP server returns a 302 status code, does the rel-tag have meaning? Is there a formal rule that indexers should follow the link to the final, resolved destination? Or is there a formal rule that a rel tag should be ignored if URL of its link does not return a status code of 200?''
* ..next answer
</li>
</ol>

===CSS selector===
*How do you write a CSS selector for rel-tag?
** <code>a[rel~="tag"] { color: green }</code>

===Are tags case sensitive?===
*Are tags case sensitive. Is "Dog" the same tag as "dog" and "DOG"?
**{{AwaitingAnswer}}

===Multi-word tags===
*How should a multi-word tag be made? For instance, if using Wikipedia as a name space, a page about a Black Redstart (a bird) would be tagged '''Black_Redstart''', with an underscore [http://en.wikipedia.org/wiki/Black_Redstart]. Is there any way of aliasing alternatives ("BlackRedstart", "Black-Redstart", etc.)? Is any particular format preferable?
** Existing bevavior
*** delicious supports combined tags
*** flickr supports multi-word tags with spaces but collapses spaces when searching
*** ma.gnolia supports multi-word tags with spaces
*** technorati supports multi-word tags with spaces
**{{AwaitingAnswer}}

===Tags with file extensions===
*Is <code><a rel="tag" href="<nowiki>http://example.com/cheese.htm</nowiki>">cheese</a></code> a valid tag for "cheese"? Ditto ".asp" or ".php" variants? If not, why not?

Any file-name extension in the last path segment is part of the tag value:

*<nowiki>http://example.com/cheese.htm</nowiki> ⇒ cheese.htm
*<nowiki>http://example.com/cheese.asp</nowiki> ⇒ cheese.asp
*<nowiki>http://example.com/cheese.php</nowiki> ⇒ cheese.php

The [[rel-tag|rel-tag specification]] is clear on how to extract a tag from a URL. Special treatment for file-name extensions is not part of the extraction. Brian Suda gave an [http://microformats.org/discuss/mail/microformats-discuss/2007-February/008538.html explanation on the microformats-discuss list]. Consider the following URLs, the tags that the following URLs give under the current specification, and the effect of requiring special treatment for file-name extensions on the tags that the following URLs give.

*http://en.wikipedia.org/wiki/.htaccess
*http://en.wikipedia.org/wiki/.Net
*http://en.wikipedia.org/wiki/India.Arie
*http://en.wikipedia.org/wiki/ASN.1
*[http://en.wikipedia.org/wiki/L.I.E. http://en.wikipedia.org/wiki/L.I.E.]

===What about Scope?===
Since rel-tag is a feature used in many other microformats, the question often arises: "What is the scope of the tag?" For instance, a rel-tag may appear inside of an [[xfolk xFolk]] entry and on first glance it may appear that the tag should only apply to that entry. However, current publishing practice seems to indicate anything appearing on a page is likely related to the content of the page. Therefore, the interpretation is that not only does the rel-tag apply its direct container but to all containers and to the document as a whole; it contains the xFolk entry. This is a departure from strict knowledge theory in favor of real-world usage.

As another example, you may link to your friend Joe with XFN and hCard, indicating in his categories that Joe is interested in swimming, which you loathe. Since the article is primarily about you and not about Joe's hobbies and because the rel-tag is inside an hCard, you may expect that the rel-tag does not apply to the document; however, the document does contain information about swimming, albeit tiny, namely that your friend likes it. In this way, rel-tag is binary: it indicates direction (yes or no) but not magnitude. This equivalent to a free-text search sans [[http://en.wikipedia.org/wiki/tf-idf tf-idf]]; i.e. without a notion of term relevance.

The upshot of this is that rel-tags can have downward scope but not upward scope.

==Related pages==
{{rel-tag-related-pages}}
**{{AwaitingAnswer}}

rel-tag-faq

2006-03-24T13:55:14Z

EtanWexler: RewriteRule correction

rel-tag-faq

2006-03-24T13:52:46Z

EtanWexler: mod_rewrite examples; URL syntax clarification; typographical, hypertextual, and editorial niceties

class-design-pattern

2005-11-20T06:48:13Z

EtanWexler: /* See Also */

= Class design pattern =

== Purpose ==
Use the [[class-design-pattern]] to indicate semantic meaning about XHTML elements

== How to use it ==
* add the microformat information the <code>class</code> attribute of an enclosing element. <code>class</code> attributes allow for multiple values by space separating values.
* if an appropriate enclosing element is not available, use <code>span</code> or <code>div</code> as appropriate to add one.

== Description ==

This is one of the most frequently occurring design patterns in microformats. Semantic meaning can be indicated on XHTML content by using the <code>class</code> attribute of an enclosing element. For example, [[hcard]] adds information indicating that certain elements are a vCard URL, a Full Name and Organization by the class design pattern:

<pre><nowiki>
<div class="vcard">
<a class="url fn" href="http://tantek.com/">Tantek Çelik</a>,
<span class="org">Technorati</span>
</div>
</nowiki></pre>

Note especially the preceding example:

* the section of the XHTML document that the microformat is being applied to is defined by <code>class="vcard"</code>. This is very common among non-trivial microformats.
* the use of both inline (<a> and <span>) and block (<div>) level elements. This provides the microformat designer with a range of options for inserting semantic information without interfering with existing presentation
* the use of multiple class names on a single element (such as <code>"url fn"</code>). This allows:
** single elements to have multiple meanings
** allows adding semantics to existing presentation

== See Also ==
* [[Main_Page#Design_Patterns|All microformat design patterns]]
* John Udel [http://weblog.infoworld.com/udell/2004/02/09.html writes] about multiple class names
* [http://www.w3.org/TR/REC-html40/struct/global.html#adef-class HTML 4.0 defintion of 'class'], including notes about multiple class names

class-design-pattern

2005-11-20T06:46:36Z

EtanWexler: “use of multivalued CSS class elements” becomes “use of multiple class names on a single element”

= Class design pattern =

== Purpose ==
Use the [[class-design-pattern]] to indicate semantic meaning about XHTML elements

== How to use it ==
* add the microformat information the <code>class</code> attribute of an enclosing element. <code>class</code> attributes allow for multiple values by space separating values.
* if an appropriate enclosing element is not available, use <code>span</code> or <code>div</code> as appropriate to add one.

== Description ==

This is one of the most frequently occurring design patterns in microformats. Semantic meaning can be indicated on XHTML content by using the <code>class</code> attribute of an enclosing element. For example, [[hcard]] adds information indicating that certain elements are a vCard URL, a Full Name and Organization by the class design pattern:

<pre><nowiki>
<div class="vcard">
<a class="url fn" href="http://tantek.com/">Tantek Çelik</a>,
<span class="org">Technorati</span>
</div>
</nowiki></pre>

Note especially the preceding example:

* the section of the XHTML document that the microformat is being applied to is defined by <code>class="vcard"</code>. This is very common among non-trivial microformats.
* the use of both inline (<a> and <span>) and block (<div>) level elements. This provides the microformat designer with a range of options for inserting semantic information without interfering with existing presentation
* the use of multiple class names on a single element (such as <code>"url fn"</code>). This allows:
** single elements to have multiple meanings
** allows adding semantics to existing presentation

== See Also ==
* [[Main_Page#Design_Patterns|All microformat design patterns]]
* John Udel [http://weblog.infoworld.com/udell/2004/02/09.html writes] about multi-valued CSS elements
* [http://www.w3.org/TR/REC-html40/struct/global.html#adef-class HTML 4.0] defintion of 'class', including notes about multivalues

media-metadata-examples

2005-11-18T00:38:12Z

EtanWexler: “foo.com” becomes “example.com”

This is an exploratory page to be used for storage of various multimedia metadata profiles currently in use around the web. As this is a very, very early exploration, we should include as many types of multimedia as possible in the opening discussion - but please be sure to place your profiles in the correct portion of this page.

= Purpose of this exploration (or : The Problem) =

The purpose of the studies on this page is to determine the feasibility and demand for a flexible, semantic markup format for providing metadata alongside linked multimedia files. Typically, this metadata is stored within the header of the media file itself - which has massive implications for any application where metadata is to be indexed, searched, or made externally accessible. Of course, even if you could easily access the correct portions of a media file remotely, you'd still have to cope with a multitude of open and proprietary metadata formats, each with it's own distinct fieldset, nomenclature and storage method.

This study aims to make a start at solving this problem.

== Contributors ==

These folks have contributed real-world examples and research to this document, and are interested in helping with a solution.

* Christopher Allen
* Dougal Campbell
* Dr. Ernie
* Rohit Khare
* Ryan King
* Kevin Marks
* Lisa Rein
* Dan Glegg
* Chris Messina

If you contribute new real-world examples or research, and wish to help with a solution, please add your name as well.

= Examples on the Web today =

* ...
* ...

= Current / Previous Standards =

== Still image ==

* [http://www.exif.org/Exif2-2.PDF EXIF]
* [http://www.tasi.ac.uk/2000/09/rdfmeta/ RDF for self-describing images]
* [http://archive.dstc.edu.au/RDU/staff/jane-hunter/PNG/paper.html An Indexing and Querying System for Online Images Based on the PNG Format and Embedded Metadata]
* [http://www.w3.org/TR/photo-rdf/ Describing and retrieving photos using RDF and HTTP]
* [http://www.pheed.com/pheed/ Pheed RSS extension for photo syndication]

== Audio ==

* [http://www.id3.org/ ID3v2]

* iTunes
** Album : String
** Artist : String
** Beats Per Minute : Number
** Bit Rate : Number
** Comment : Blob
** Composer : String
** Genre : String or Foreign ID
** Disc Number : Number
** Kind : Proprietary - could be implimented as MIME type
** My Rating : Number < 5 (actually an integer from the range 0-100. 1-5 "stars" implemented by incrementing by 20)
** Sample Rate : Number
** Size : Number
** Time : Number
** Track Number : Number
** Year : Number
**Additional metadata used internally by the application : Date Added (Timestamp), Date Modified (Timestamp), Equalizer (foreign ID), Play Count (Number), Grouping (Internal)
**Noteable absences : Tags, [[rel-license|License]], Copyright year. Also note common complaints about [http://www.everything2.com/index.pl?node_id=1707402 ID3 and classical music].

* [http://www.xspf.org/ XSPF] (see also [http://gonze.com/playlists/playlist-format-survey.html A survey of playlist formats] and [http://www.xspf.org/xspf-v0.html The XSPF Playlist Format, version 0])
** album
** creator
** duration
** info
** title
** trackNum

== Podcasts ==

* '''iTunes podcast:''' http://phobos.apple.com/static/podcast_specifications.pdf
(HTML version of spec: [http://labs.commerce.net/~rohit/How%20To%20Publish%20a%20Podcast%20on%20iTunes%20Music%20Store.html local archive], [http://labs.commerce.net/~rohit/iTunesRSS.html updated version from Apple Chapter Tool Beta docs], [http://phobos.apple.com/static/iTunesRSS.html online copy at Apple])

iTunes release 4.9 was widely heralded as an advance for mainstream acceptance of podcasting. However, while some advocates resist even the fragment of a trademarked name in the label for the phenomenon, the use of "itunes:" in the namespace is one of many design decisions in Apple's original specification that became focal points of debate. While Apple has a tradition of working on breakthrough features very quietly, they have been open to public input after its initial release. Many [http://daringfireball.net/2005/07/podcast_pocket other bloggers] have [http://usefulinc.com/edd/blog/contents/2005/06/28-rss-apple-itunes/read chronicled] [http://www.intertwingly.net/blog/2005/07/05/Insensitive-iTunes some of the feedback], as well as some [http://tantek.com/log/2005/07.html#d10t0130 face-to-face discussions].

A mailing list may be coming soon...

* '''Media RSS:''' http://search.yahoo.com/mrss

Media RSS has [http://www.ysearchblog.com/archives/000111.html been in the works longer], but doesn't have the overnight-adoption advantage of iTunes. However, it has a much broader ambit, including [http://www.ysearchblog.com/archives/000060.html video]; and a much broader [http://groups.yahoo.com/group/rss-media/ community of interest].

=== A Podcasting Microformat? ===

The best starting point for understanding these two proposals is [http://www.w3.org/2005/07/media-and-rss W3C's summary table, by Karl Dubost].

There are (at least) two paths to consider when 'porting' these proposals into Microformats:
# '''Standalone.''' What is the most straightforward rendering of each proposal into XHTML? This keeps the interests of the developers of ''consuming'' applications foremost: how can the migration be made as painless as possible?
# '''Refactored.''' Given the existing core of Microformats, what is the minimal (!) necessary to add on to RelLicense, RelTag, hReview, and so forth? This favors (we'd hope) content ''publishing'' applications: how can the marginal migration costs of adding media be made as painless as possible.

Mapping the existing specs requires understanding the data definitions set forth in each specification, and finding the optimal equivalents (where available). The following is a partial summary of one possible mapping:

==== Comparison Table ====

{| border="1" cellpadding="5" cellspacing="0" style="border:1px solid grey;"
|+ Comparing existing proposals
! Aspect !! Apple !! Yahoo! !! Microformat?
|-
| '''Categorization'''
|| <itunes:category> <br> <itunes:keywords>
|| <media:category>
|| [[rel-tag | RelTag]] - requires a way to do sub categories?
|-
| '''Rating''' || <itunes:explicit>|| <media:adult> || [[rel-tag | RelTag]]
|-
| '''Description''' ||<itunes:subtitle> <br> <itunes:summary>|| <media:text> || XHTML (e.g. < blockquote > )
|-
| '''Authorship'''
|| <itunes:author> <br> <itunes:owner> <br> <itunes:name> <br> <itunes:email>
|| <media:credit>
|| <cite> <br> [[hcard|hCard]]
|-
| '''Metadata''' || <itunes:duration> <br> <itunes:image>|| <media:thumbnail> <br> <media:hash> <br>
<media:content
url="http://www.example.com/movie.mov"
fileSize="12216320"
type="video/quicktime"
isDefault="true"
expression="full"
bitrate="128"
framerate="25"
duration="185"
height="200"
width="300" />
|| ''needs a new microformat'' <br> e.g., <dl><dt>proposal for duration</dt><dd><pre><abbr class="duration" title="00:27:35">
27 minutes, 35 seconds
</abbr></pre>
-- [[User:jkinberg|jkinberg]] 11:51, 19 Sept 2005 (PDT))
</dd></dl>
|-
| '''Licensing''' || <itunes:block> <br> <copyright> <br> <link>|| Not explicitly mentioned || [[rel-license | RelLicense]]
|-
|}

== Video ==
* [http://www.exif.org/Exif2-2.PDF EXIF] - (Yes, the spec deals with video taken by still cameras. -- RyanKing)
* [http://www.chiariglione.org/mpeg/standards/mpeg-7/mpeg-7.htm MPEG-7] - MPEG-7, formally named "Multimedia Content Description Interface", is a standard for describing the multimedia content data that supports some degree of interpretation of the information meaning, which can be passed onto, or accessed by, a device or a computer code. (Very powerful, but you have to pay for documentation -- [[User:ChristopherA|ChristopherA]] 01:53, 29 Jun 2005 (PDT))
* [http://www.w3.org/AudioVideo/ SMIL] - Synchronized Multimedia Integration Language (SMIL, pronounced "smile") enables simple authoring of interactive audiovisual presentations. (Not exactly video, but has a lot of useful video-related features in it. -- [[User:ChristopherA|ChristopherA]] 01:55, 29 Jun 2005 (PDT))
* [[video-metadata-model| Video Metadata Model - a starting point]]

== Interactive ==
* [http://www.w3.org/Graphics/SVG/ SVG]
* [http://www.w3.org/AudioVideo/ SMIL]
* QTVR?

== Offline Media ==
* [http://xspf.org XSPF] (media may be either offline or online)

=== Printed Publications (books/magazines) ===
* [http://amazon.com/ Amazon]

=== Movies ===
* [http://imdb.com/ IMDB]
* [http://amazon.com/ Amazon]

=== Music ===
* [http://freedb.org/ FreeDB]
* [http://musicbrainz.org/ MusicBrainz]
* [http://amazon.com/ Amazon]

= Comments =

* See separate [[media-metadata-issues]] document.

= Related LInks =

* [[video-metadata-models]]

hcard-brainstorming

2005-11-12T06:21:43Z

EtanWexler: “text/directory” versus “text/vcard”

= hCardBrainstorming =
__TOC__
== Authors ==
* [http://suda.co.uk/ Brian Suda]
* [http://tantek.com/log/ Tantek Çelik], [http://technorati.com Technorati, Inc]

== Examples ==

* See [[hcard-examples]].
** We should provide 1:1 hCard examples for each example in [http://www.ietf.org/rfc/rfc2426.txt RFC 2426].

=== John Smith ===
<pre><nowiki>
BEGIN:VCARD
VERSION:2.0
N:Smith;John
FN:John Smith
TEL;CELL:314-123-4567
TEL;FAX:314-123-4568
TEL;WORK:314-123-4569
URL:www.example.com
org:Example Oragnization;Marketing and Communications
EMAIL;INTERNET:john.smith@example.com
TITLE:Director, Marketing & Web Services
ADR;;123 Main Street;Any Town;MO;12345;USA
NOTE;quoted-printable:"A personal signature here"
END:VCARD
</nowiki></pre>
This is one way to encode the vCard in HTML
<pre><nowiki>
<div class="vcard">
<a href="mailto:john.smith@example.com">
<span class="fn n">
<span class="given-name">John</span>
<span class="family-name">Smith</span>
</span>
</a><br />


<span class="tel">314-123-4567</span><br />
<span class="tel">314-123-4568</span><br />
<span class="tel">314-123-4569</span><br />

<p>I work for
<span class="org">
<a href="http://www.example.com" class="organizational-name">Example Oragnization</a>
in the <span class="organizational-unit">Marketing and Communications</span>
</span>
department as <span class="title">Director, Marketing & Web Services</span>
</p>

<address>
<span class="street">123 Main Street</span><br />
<span class="locality">Any Town</span>,
<span class="region">MO</span>
<span class="postal-code">12345</span><br />
<span class="country-name">USA</span><br />
</address>

<div class="note">A personal signature here</div>

</div>
</nowiki></pre>
This would display as:<br />
[mailto:john.smith@example.com John Smith]<br />
314-123-4567<br />
314-123-4568<br />
314-123-4569<br />
<br />
I work for [http://www.example.com/ Example Oragnization] in the Marketing and Communications department as Director, Marketing & Web Services<br />
<br />
123 Main Street<br />
Any Town, MO 12345<br />
USA<br />
<br />
A personal signature here<br />
<br />

=== Baron von Münchhausen ===
<pre><nowiki>
BEGIN:VCARD
VERSION:2.0
N:Hieronymus;Karl;Friedrich;;Baron von Münchhausen;
FN:Karl Friedrich Hieronymus
NICKNAME:Baron von Münchhausen,The Baron of Lies,Freddy
SORT-STRING:Hieronymus
END:VCARD
</nowiki></pre>
This is one way to encode the vCard in HTML
<pre><nowiki>
<div class="vcard" xml:lang="de">
<span class="n">
<span class="fn">
<span class="given-name">Karl</span>
<span class="additional-names">Friedrich</span>
<span class="family-name"><span class="sort-string">H</span>ieronymus</span>,
</span>
<span class="honorific-suffixes">Baron von Münchhausen</span>
</span>
<h2>Nicknames</h2>
<ul class="nicknames">
<li>Baron von Münchhausen</li>
<li>The Baron of Lies</li>
<li>Freddy</li>
</ul>
</div>
</nowiki></pre>
This would display as:<br />
Karl Friedrich Hieronymus, Baron von Münchhausen<br />
<br />
Nicknames
* Baron von Münchhausen
* The Baron of Lies
* Freddy

=== Examples from the RFC ===
These examples were taken from the vCard RFC 2426.
<pre><nowiki>
N:Public;John;Quinlan;Mr.;Esq.
NICKNAME:Jim,Jimmie
PHOTO;VALUE=uri:http://www.abc.com/pub/photos/jqpublic.gif
LOGO;VALUE=uri:http://www.abc.com/pub/logos/abccorp.jpg
BDAY:1987-09-27T08:30:00-06:00
TEL;TYPE=work,voice,pref,msg:+1-213-555-1234
EMAIL;TYPE=internet:jqpublic@xyz.dom1.com\
TZ:-05:00
CATEGORIES:INTERNET,IETF,INDUSTRY,INFORMATION TECHNOLOGY
NOTE:This fax number is operational 0800 to 1715 EST\, Mon-Fri.
UID:s19950401-080045-40000F192713-0052
URL:http://www.swbyps.restaurant.french/~chezchic.html

<div class="vcard">
<a href="mailto:jqpublic@xyz.dom1.com" class="email n">
<span class="honorific-prefixes">Mr.</span> <span class="given-name">John</span>
<span class="additional-names">Quinlan</span> <span class="family-name">Public</span>
<span class="honorific-suffixes">Esq.</span>
</a>
<ul class="nickname">
<li>Jim</li>
<li>Jimmie</li>
</ul>
<img src="http://www.example.com/pub/photos/jqpublic.gif" class="photo" />
<img src="http://www.example.com/pub/logos/abccorp.jpg" class="logo" />

<abbr title="1987-09-27T08:30:00-06:00" class="bday">Sept. 27th 1987</abbr>


<div class="tel">+1-213-555-1234</div>


<abbr title="-050000" class="tz">Eastern Standard Time</abbr>

<ul class="categories">
<li>INTERNET</li>
<li>IETF</li>
<li>INDUSTRY</li>
<li>INFORMATION TECHNOLOGY</li>
</ul>

<div class="note">This fax number is operational 0800 to 1715 EST\, Mon-Fri.</div>
<a href="http://www.swbyps.restaurant.french/~chezchic.html" class="url"></a>
</div>
</nowiki></pre>

<pre><nowiki>
BEGIN:vCard
VERSION:3.0
FN:Frank Dawson
ORG:Lotus Development Corporation
ADR;TYPE=WORK,POSTAL,PARCEL:;;6544 Battleford Drive;Raleigh;NC;27613-3502;U.S.A.
TEL;TYPE=VOICE,MSG,WORK:+1-919-676-9515
TEL;TYPE=FAX,WORK:+1-919-676-9564
EMAIL;TYPE=INTERNET,PREF:Frank_Dawson@Lotus.com
EMAIL;TYPE=INTERNET:fdawson@earthlink.net
URL:http://home.earthlink.net/~fdawson
END:vCard

<div class="vcard">
<a href="http://home.earthlink.net/~fdawson" class="url fn">Frank Dawson</a>
<div class="org">Lotus Development Corporation</div>


<div class="adr">
<span class="street-address">6544 Battleford Drive</span>
<span class="locality">Raleigh</span>
<span class="region">NC</span>
<span class="postal-code">27613-3502</span>
<span class="country-name">U.S.A.</span>
</div>


<div class="tel">+1-919-676-9515</div>
<div class="tel">+1-919-676-9564</div>


<a class="email" href="mailto:Frank_Dawson@Lotus.com">Frank_Dawson@Lotus.com</a>
<a class="email" href="mailto:fdawson@earthlink.net">fdawson@earthlink.net</a>
</div>

BEGIN:vCard
VERSION:3.0
FN:Tim Howes
ORG:Netscape Communications Corp.
ADR;TYPE=WORK:;;501 E. Middlefield Rd.;Mountain View;CA; 94043;U.S.A.
TEL;TYPE=VOICE,MSG,WORK:+1-415-937-3419
TEL;TYPE=FAX,WORK:+1-415-528-4164
EMAIL;TYPE=INTERNET:howes@netscape.com
END:vCard

<div class="vcard">
<a href="mailto:howes@netscape.com" class="fn email">Tim Howes</a>
<div class="org">Netscape Communications Corp.</div>


<div class="adr">
<span class="street-address">501 E. Middlefield Rd</span>
<span class="locality">Mountain View</span>
<span class="region">CA</span>
<span class="postal-code">94043</span>
<span class="country-name">U.S.A.</span>
</div>


<div class="tel">+1-415-937-3419</div>
<div class="tel">+1-415-528-4164</div>

</div>

</nowiki></pre>

=== Using RFC2806 with hCard ===

[http://www.ietf.org/rfc/rfc2806.txt RFC 2806] defines the telephone scheme "tel:", "fax:" and "modem:" to handle phone communications with URIs in the same way, "mailto:" is defined for email. It's part of the list or registered schemes by IANA : [http://www.iana.org/assignments/uri-schemes Uniform Resource Identifier (URI) SCHEMES]

<pre><nowiki>
tel telephone [RFC2806]
fax fax [RFC2806]
modem modem [RFC2806]
</nowiki></pre>

It is practical to write your tel number like this.

<pre><nowiki>
<a class="tel" href="tel:+1-919-555-7878>+1-919-555-7878</a>
</nowiki></pre>

or even

<pre><nowiki>
<a class="tel" href="tel:+1-919-555-7878>Mr Smith's phone</a>
</nowiki></pre>

You can add support for "tel:" to your desktop and to your browser

* For Gnome, edit ~/.gnome/Gnome and add something to the URL Handlers section. (Dan Connolly uses this to get galeon to launch telnum from [http://dev.w3.org/cvsweb/2001/telagent/ telagent sources] for tel URIs)
* In Mozilla, [http://dizzy.mozdev.org/ Dizzy]
* In Internet Explorer, [http://msdn.microsoft.com/workshop/networking/pluggable/overview/overview.asp Asynchronous Pluggable Protocols]

On the CSS front… You could for example add automagically an icon. I have put the property !important for those who wants to add it to their own stylesheet in their browsers, so they know type of links when browsing.

<pre><nowiki>
a[href^="tel:"]:before {
content: '\260f ' !important;
padding-left: 20px !important; }

a[href^="mailto:"]:before {
content: '\2709 ' !important;
padding-left: 20px !important; }
</nowiki></pre>

== Encoding "modern" attributes ==

Since vCard was first established, various interactive communication technologies and addressing schemes have been widely adopted. Although there aren't specific properties for these technologies / addressing schemes, they can be captured as URLs or email addresses as follows:

* AOL Instant Messenger (AIM) ids, simply store "aim:goim?screenname=" urls, e.g.
** <code><a class="url" href="aim:goim?screenname=yournamehere">...</code>
* iChat mac.com addresses, simply store "@mac.com" email addresses, e.g.
** <code><a class="email" href="mailto:steve@mac.com">...</code>
* MSN Instant Messenger, you can simple store "@hotmail.com" or "@msn.com" or "@passport.com" email addresses.
* Internet Relay Chat (IRC), use "irc:" URLs.

== Encoding Company data as a Business Card (proposal) ==
In the wild there are several hCards that do not currently validate because they are businesses that have omitted the "fn" property in favour of the "org" property.
# if there is an "fn" property use that value
# if the "fn" property is missing, but an "org" property is available, duplicate the value for both
# the "n" property is manditory, and must somehow be derived from "org", probably use the entire value as "family-name"

== CSS Styles ==
Not only can you create semantics with the hCard values, but you can add CSS styles to them as well. You are free to style the terms in any way you want, but here we can list a few ideas for how to style terms.

If you want to encode hCard data, but do NOT want to display it in the HTML code, then you can hide that tag in CSS with the following code:
<pre><nowiki>
<span style="display: none">Hidden Data</span>
</nowiki></pre>
Transforming applications will still find the data and use it when converting hCards to vCards.

== Auto-Discovery ==
There is currently a debate over the best way to add an auto discovery link to your HTML to extract the vCard.

On the page with the hCard encoding, the best link would be as follows:
<code><nowiki> <link rel="alternate" type="text/vcard" href="..." /> </nowiki></code>
this HTML page is an alternate view of the vCard.

[[User:EtanWexler|EtanWexler]] disagrees with the value of the “type” attribute. The [http://www.iana.org/ Internet Assigned Numbers Authority] has no registration for a “text/vcard” type. The [http://www.iana.org/assignments/media-types/text/ registered and appropriate type] for vCard entities is “text/directory”, as defined in Internet RFC 2425, “[http://www.rfc-editor.org/rfc/rfc2425.txt A MIME Content-Type for Directory Information]”. RFC 2426, “[http://www.rfc-editor.org/rfc/rfc2425.txt vCard MIME Directory Profile]”, specifies the vCard profile for “text/directory” entities, which profile the MIME/HTTP header field “Content-Type” would indicate with a “profile” parameter whose value is “VCARD”. It is unclear whether the HTML/XHTML “type” attribute allows values with parameters. On 2004-05-23, [http://bjoern.hoehrmann.de/ Björn Höhrmann] sent to the [http://www.w3.org/2002/05/html/charter HTML Working Group] a [http://www.w3.org/mid/40ccdc4d.97400945@smtp.bjoern.hoehrmann.de request for clarification] on the issue.

When on a different page, referencing that encoded page in the href would ''not'' be an alternate view of the current page. So a different rel type must be established to decribe that relationship. The ideas vary from specific to vague. The list and categories follow:
<pre><nowiki>
rel="contactinfo"
rel="profile"
rel="author"
rel='PIM'
rel='person'
rel='about'
rel='contact'
rel='hcard'
rel='microformat'
</nowiki></pre>
Example of mixing two rel types to a single page.
rel="hcard xfn"

Note: using rel="vcard" indicates a link directly to a vCard. If the document links to an hCard instead, the indication is untrue and inappropriate.

=== Auto-Discovery for XFN ===

An author will typically their XFN information on a specific page, rather than all pages. In particular, a specific page separate from the home page of their blog, and thus it would be useful to have an explicit rel value to assist in auto-discovery of XFN information.

This was suggested by Jens Alfke on 20050606 at the WWDC blogger's dinner.

== Issues with vCard Applications ==
The following are major vCard application and a description of the features they support and don't support.

=== Apple Address Book ===
* There are issues with importing UTF-8 vCards
* LOGO property is not supported
* only ONE URL is supported
* PHOTO property can only be encoded, no URL references allowed
* SOURCE property is not supported

=== Windows Address Book ===
(not yest tested)

=== Mozilla Thunderbird ===
(not yest tested)

=== Other? ===
(not yest tested)

== Open Questions ==

Q: since many of the components would be using CSS classes for encoding data, it is possible to MIX two different profiles. (e.g. hCard and XFN) There are no real constraints on where/how to enforce class names, these are based on the html profile, since it is difficult to associate the text within the attribute to a specific profile.

<pre><nowiki>
...
<a href="mailto:joe.smith@example.com" class="fn" rel="met">Joe Smith</a>
...
</nowiki></pre>

-- [http://suda.co.uk/ Brian Suda]

Q: Preserving White space? Should the transforming applications preserve extra white space characters? For example:
<pre><nowiki>
<a href="http://mywebsite.com/" class="fn n">
<span class="given-name">John</span>
<span class="other-names">Q.</span>
<span class="family-name">Public</span>
</a>
</nowiki></pre>

When transformed into a vCard, the N property will pick apart the span tags and create the value for N correctly seperated by colons. The FN property will take a string and simply display it. There are two possible renderings for FN:
<pre><nowiki>
John Q. Public

John
Q.
Public
</nowiki></pre>

Either the white-space is preserved or it is not. Which should the transforming applications render?

-- [http://suda.co.uk/ Brian Suda]

A: The parsing application should follow the white space collapsing rules of the mime type it retrieves. I.e. if it retrieves a "text/html" document, it should do HTML white space collapsing.

-- [http://tantek.com/log/ Tantek]

Many of the Questions and Answers are relevant to both ["hCal"] and hCard.

Q: Would it be appropriate to wrap the name of the vCard owner with <dfn/>? This may give the hCard some added semantic value in the XHTML document.
<pre><nowiki>
<span class="agent">
<span class="vcard">
<span class="email">
<a class="internet" href="mailto:jfriday@host.com">
<dfn>
<span class="fn">Joe Friday</span>
</dfn>
</a>
</span>
<span class="tel">+1-919-555-7878</span>
<span class="title">Area Administrator, Assistant</span>
</span>
</span>
</nowiki></pre>
-- [http://www.ben-ward.co.uk/ Ben Ward]

== Applications ==
Applications that are hCard aware or can convert hCard to vCard formats.

=== Copy hCards favelet(s) ===
* I think a Favelet would work nicely here. When you find a page that is hCard friendly, you click the favlet and you get yourself a vCard. This is done! See X2V in the implementations section of the [[hcard|hCard]] spec.

=== Distributed Commentor Icons ===

* See [http://thedredge.org/2005/06/using-hcards-in-your-blog/ using hCards in your blog] for an example of hCards used for comment authors (commentors). The system used there, "Gravatars", is a centralized site that serves commentor icons that requires login etc.

What if we gave each commentor the option of hosting their own icon?

A distributed commentor icon implementation could work like this:

# Given the URL of a commentor, look for an <code><address></code> element with classname of "vcard" at the commentor's URL. The <code><address></code> element is supposed to be the contact information for the page (see [[hcard-faq|hCard FAQ]] for more info), so this makes sense.
# Next, look for the first element inside that hcard that has a classname of "logo".
# Hopefully that element is an <code><img></code>, and if so, use its src to get the commentor's icon.
# Presto. You've got distributed commentor icons!

== Spam prevention ==
hCard uses <code>mailto:</code> links, and therefore
it automatically "inherits" the disadvantage of <code>mailto:</code> links:
These links can be easily detected by emails spiders (used by spammers).

There are ways to prevent email address detection by simple email spiders, while
still retaining full compatibility with (X)HTML applications.
One common way is to "encode" the the "m" of "mail" and "@" with character entities:

Example of the original link:
<pre><nowiki>
<a class="email" href="mailto:john.smith@example.com">john.smith@example.com</a>
</nowiki></pre>

Example of the "encoded" link:
<pre><nowiki>
<a class="e&#109;ail" href="&#109;ailto:john.smith&#064;example.com">john.smith&#064;example.com</a>
</nowiki></pre>

Simple email spiders which do not do character entity decoding will therefore not be able to find your email address.

''Note:'' Perhaps there are or will be email spiders which can decode entities, so the this technique will only help with some (cheap) email spiders.
(See also: http://rbach.priv.at/Misc/2005/EmailSpiderTest)

== Tutorials ==
* How to hCard encode entries in Popular blog software.
* Good reasons to publish your hCard
** as a business, get people to put you in their address book so they'll find you later
** as a business with an email list, get people to add you (with email address) to their address book so that your email list works via whitelisting via the address book.

== Parsing ==
See separate [[hcard-parsing|hCard parsing]] page.

== TODO ==

* The [[hcard-profile]] needs verification and perhaps a URL for retrieving the actual XMDP, rather than as <pre> text on a wiki page.
* Complete translating the examples from the vCard spec into hCard, and place them on a separate hCard examples page.
* Create a "rich" but realistic hCard example, say for example for a salesperson, who wants to put a whole bunch of contact information on their website in order to be found/contacted easily.
* Provide examples of how to encode instant messaging (IM) accounts. Figure out what would the mailto: or aim: URL in hCard look like in vCard. And take a look at what vCard applications do today with IM addresses.

== References ==
=== Normative References ===
* [http://www.ietf.org/rfc/rfc2426.txt RFC 2426] vCard RFC
* [http://www.ietf.org/rfc/rfc2397 RFC 2397] data URI RFC
* [http://gmpg.org/xmdp/ XMDP]
=== Informative References ===
* [http://www.imc.org/pdi/ Personal Data Interchange (PDI) at the Internet Mail Consortium]
* [http://tantek.com/log/2004/07.html#d27t1049 Markup language design notes]
* [http://tantek.com/log/2002/12.html#L20021216t2238 A Touch of Class]

== Other Implementations/Ideas ==
* [http://www.w3.org/TR/2001/NOTE-vcard-rdf-20010222/ Representing vCard Objects in RDF/XML] This could allow conversion of vCard data from XHTML to RDF and from RDF to XHTML
* It would also be possible to convert XFN and hCard to FoaF and back.

== Rejected Suggestions ==

Suggestion: ''The use of class="url" on an <a> tag to represent an hCard URL property is redundant. By virtue of the <a> tag you know this is a URL.''

Rejected. This is a bad suggestion because although it appears to reduce redunancy and keep things cleaner, it also creates a few problems. Without explicitly noting that this is a URL then any <a> tags within a 'vcard' would be considered a URL, for example:
<pre><nowiki>
<span class="vcard">
...
<ul class="categories">
<li><a href="http://w3c.org">W3C</a></li>
</ul>
...
</span>
</nowiki></pre>

There is no way to "turn-off" the encoding of the W3C URL, whereas if "url" needed to be explicitly listed in the class attribute list, then by NOT listing it you could effectively turn it off.

User:EtanWexler

2005-11-12T03:08:42Z

EtanWexler:

= a-mu-zu-men-ti =
“Floating World”