2005-01-18 - Posted on the Google Blog by Matt Cutts, Google Software Engineer and Jason Shellon, Blogger Program Manager
From now on, when Google sees the attribute
rel="nofollow" on hyperlinks, those links won't get any credit when we rank websites in our search results.
<a rel="nofollow" href="http://www.example.com/">Anchor Text</a>
This is a joint effort by the major players in the search and blog space to curtail and/or prevent what is referred to as Comment Spam. Those search engines who have agreed to the new link relationship attribute are...
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.
Let's clarify a few things about link element relationships and anchor element relationships. We do believe some of the terminology is getting mixed up based on our interpretation of the standards.
Link relationships have been around for quite some time. We've been using them for years to group collections of documents together.
REL attribute describes the relationship that destination plays with respect to the source (the current document). The REV attribute can be used to define the reverse relationship. A link from document A to document B with REV=relation expresses the same relationship as a link from B to A with REL=relation. Note that relationship names are case insensitive using the same definition as given above for anchor name values.
Thanks to <a rel="sponsor">SEO Consultants Directory</a> for support...
Following the precedent set by HTML 2.0, REL and REV can take a space separated list of relationship values. Note that REL and REV are also used with the LINK element. Relationship values can be defined in profiles.
For instance, links defined by the LINK element may describe the position of a document within a series of documents.
The roles of a link defined by A or LINK are specified via the rel and rev attributes.
The term granular was mentioned by encyclo during a recent discussion on the topic of
rel="nofollow" at WebmasterWorld. If the search engines really want to get granular, this would probably be the best method of doing so...
Although the above discusses the link element, this also applies to the anchor element.
<a rel="sponsor" href="http://www.webmasterworld.com/">WebmasterWorld</a>
<a rev="sponsor" href="/">SEO Consultants Directory</a>
Note in the above example that I've used both
rev anchor attributes. The
rel expresses the relationship between Site A's link to Site B. The
rev expresses the reverse relationship between Site B's link to Site A.
Okay, there is much more than that. If you follow the links above and bury yourself there for a few hours, you'll find a wealth of information pertaining to A and LINK relationships.
By the way, I'm going to assume that all of those involved with this
rel="nofollow" initiative have created what is called a profile. The exact reference is as follows...
The meaning of a property and the set of legal values for that property are defined in a reference lexicon called a profile.
The value of that
rel="" is determined by the entity that is creating the profile.