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."

Formatting of the Link Relationship Attribute

rel="nofollow" href="http://www.example.com/">Anchor Text

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...

• Google - Preventing Comment Spam
• Yahoo! - A Defense Against Comment Spam
• MSN Search - Working Together Against Blog Spam

From Technorati

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.

• rel="nofolllow"

Link Element Relationships and Anchor Element Relationships

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.

From the W3C on Link Relationships

The 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 SEO Consultants Directory 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.

rel = link-types

This attribute describes the relationship from the current document to the anchor specified by the href attribute. The value of this attribute is a space-separated list of link types.

rev = link-types

This attribute is used to describe a reverse link from the anchor specified by the href attribute to the current document. The value of this attribute is a space-separated list of link types.

Granular Linking

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.