[uf-discuss] hCard UID was: hatom tumblr theme

Martin McEvoy martin at weborganics.co.uk
Wed Dec 17 11:52:04 PST 2008

Scott Reynen wrote:
> On [Dec 17], at [ Dec 17] 4:13 , Martin McEvoy wrote:
>> The above does not make any sense (to me), UID in microformats 99% of 
>> the time is hooked on the URL value, URL's are *not* globally unique 
>> to people just unique to the domain
> That may be true in some cases, but it's certainly not universally 
> true.  Here's a URL that is unique to you:
> http://microformats.org/wiki/User:WebOrganics
> Here's a URL that is unique to me:
> http://microformats.org/wiki/User:ScottReynen
> Those URLs are not OpenIDs, but are usable as UIDs.  It's not really 
> difficult to find such URLs; almost every site you use with an account 
> creates a URL that identifies you and only you.

Hello Scott.. OK that's community blogs and wiki's dealt with.......
>> many people share urls with other people
> Sure, and such URLs should not be used as UIDs.  The use of URLs as 
> UIDs does not suggest that *every* URL makes a good UID, just that 
> there are enough to be usable.

Agreed, some people still may not have any choice.

I think (maybe) that the use of http urls in hCard for UID's is not 
compliant with hCalendar UID

" Description: The UID itself MUST be a globally unique identifier. The
   generator of the identifier MUST guarantee that the identifier is
   unique. There are several algorithms that can be used to accomplish
   this. The identifier is RECOMMENDED to be the identical syntax to the
   [RFC 822] addr-spec. "


Which seems to suggest that maybe an email address is more favourable as 
a UID not a http reference?

I spotted this today


apparently you can use the abbr pattern to mark up a UID which is a 
great fall back solution because Authors can specify a UID that they 
know is unique.

<abbr class="uid" title="urn:isbn:0950788120">0 9507881-2-0</abbr>

The above  is supported by the hCard validator and Operator, probably 
more, but not X2V for some reason

for an example of UID using the abbr design pattern


Martin McEvoy


"You may find it hard to swallow the notion that anything as large and apparently inanimate as the Earth is alive."
Dr. James Lovelock, The Ages of Gaia

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