rel-nofollow: Difference between revisions

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http://haiminhco.com.vn
http://mayphotocopyhn.com
http://ihuongdan.vn


== articles ==
== articles ==

Revision as of 14:20, 21 March 2017

<entry-title>rel="nofollow"</entry-title>

Specification 2005-01-10

Editors

Concept

Copyright

This specification is (C) 2005-2024 by the authors. However, the authors intend to submit (or already have submitted, see details in the spec) this specification to a standards body with a liberal copyright/licensing policy such as the GMPG, IETF, and/or W3C. Anyone wishing to contribute should read their copyright principles, policies and licenses (e.g. the GMPG Principles) and agree to them, including licensing of all contributions under all required licenses (e.g. CC-by 1.0 and later), before contributing.

  • Tantek: I release all my contributions to this specification into the public domain and I encourage the other authors to do so as well.
  • Kevin Marks: I release all my contributions to this specification into the public domain and I encourage the other authors to do so as well.
    • When all authors/editors have done so, we can remove the MicroFormatCopyrightStatement template reference and replace it with the MicroFormatPublicDomainContributionStatement.

Patents

This specification is subject to a royalty free patent policy, e.g. per the W3C Patent Policy, and IETF RFC3667 & RFC3668.

Abstract

RelNoFollow is an elemental microformat, one of several microformat open standards. By adding rel="nofollow" to a hyperlink, a page indicates that the destination of that hyperlink SHOULD NOT be afforded any additional weight or ranking by user agents which perform link analysis upon web pages (e.g. search engines). Typical use cases include links created by 3rd party commenters on blogs, or links the author wishes to point to, but avoid endorsing. For more specific endorsement (or lack thereof) semantics, see VoteLinks.

XMDP profile

The following is an XMDP profile for the rel-nofollow specification.

URLs

This profile is hosted as a separate XMDP file on microformats.org:

Usage

Profiles are referenced in (X)HTML files in the <HEAD> tag, e.g.: 

<head profile='http://microformats.org/profile/rel-nofollow'>

Profile

<dl class="profile">
 <dt id="rel">rel</dt>
 <dd><p>
   <a rel="help" href="http://www.w3.org/TR/html401/struct/links.html#adef-rel">
     HTML4 definition of the 'rel' attribute.</a>  
   Here is an additional value as defined in the
   <a rel="help start" href="http://microformats.org/wiki/rel-nofollow">
   rel-nofollow specification</a> 
   .</p>
  <dl>
   <dt id="nofollow">nofollow</dt>
   <dd>Indicates that the referred resource was not necessarily linked to 
       by the author of the page, and thus said reference should not afford 
       the referred resource any additional weight or ranking by user agents.
   </dd>
  </dl>
 </dd>
</dl>

examples in the wild

This section is informative. Note: There are numerous uses of rel-nofollow in the wild, this is very much an incomplete list. If your site marked up with rel-nofollow, feel free to add it to the top of this list. Once the list grows too big, we'll make a separate wiki page (rel-nofollow-examples-in-wild).

  • Netdesign Developers Network uses the rel-nofollow attribute to make search engines don't follow the "off-topic" links.
  • FunAdvice supports using the rel-nofollow tag to prevent users posting content simply for the search engine benefit, to improve the quality of the advice giving community.
  • Dog Food Coupons provides a dog food coupon collection service for dog owners. rel-nofollow is used to instruct search engine agents to not further execute link analysis and avoid endorsement of the actual merchant coupon links.
  • Pet Food Coupons While listing coupons in our Dog Food Coupons section why use the rel-nofollow tag to make sure that search engines specifically Google do not follow any links we believe have no value to the visitor.

bad examples in the wild

This section is informative. There are now numerous abuses of rel-nofollow, in particular, where it is used on *2nd party* links, rather than the original intention of *3rd party* links such as in blog comments. The primary abusers of rel-nofollow are content hosting / social network sites.

exceptions

It may seem odd to explicitly list *non* examples in an examples in the wild section, but such non-examples may be useful to help convince the bad examples in the wild to change their behavior:

normative references

informative references

  • VoteLinks can be used by an author to explicitly state their support for or against, or neutrality toward the destination of a link. Implementers implementing rel="nofollow" and VoteLinks should similarly not afford any additional weight or ranking to links with either rev="vote-abstain" or rev="vote-against".
  • Contributed from http://developers.technorati.com/wiki/RelNoFollow

open issues

These are open issues that have been raised about rel="nofollow" that have been raised in various forums, in particular, on the public W3C www-html mailing list. Once the list grows too big, we'll make a separate wiki page (rel-nofollow-issues). The issues have been grouped into four areas.

  • Definition. nofollow indicates a behavior rather than a relationship from which the behavior should be inferred as appropriate for the useragent. rel values should be nouns that indicates what the resource being referenced is in relation to the source.
  • Name. nofollow is a bad name.
    • overloading. does not mean the same as robots exclusion standards (robots.txt, meta robots) nofollow.
    • does not mean what it says. does not mean "do not follow this link", rather it means " do not add weight from this link". Asbjørn Ulsberg
    • not a noun. see above.
    • suggested alternatives:
  • Efficacy. nofollow will not affect spamming behavior.
  • Collateral Damage. If tools automatically add nofollow to all 3rd party links, then many legitimate non-spam links will be ignored or given reduced weight, and thus the destination of such links will be unfortunate casualties.

additional lists of issues

Additional lists of issues raised against rel="nofollow" can be found at the following site(s):

Matt Cutts Says No to Nofollow On Internal Links:

http://haiminhco.com.vn http://mayphotocopyhn.com http://ihuongdan.vn

articles

When this section gets too big, we can move it to rel-nofollow-articles.

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