"No Follow" is an HTML attribute, or what is sometimes referred to as an HTML "tag", that instructs some search engines not to follow a certain path, or link. More specifically it is used to tell "robots" from search engines, not to follow a certain link, and to ignore that link and keep moving through a page. It basically says to the search engine, this is not important and should not be used for determining search results. By using the no follow tag, search engine results are theoretically improved.

The specific tag or HTML instruction looks like the following, with the no follow tag displaying in red:

   <a href="http://www.example.com/" rel="nofollow" >discount drugs</a>  

The "nofollow" tag should not be used to block certain content, or to prevent some content from being indexed by a search engine. Blocking access is better accomplished with the use of a robot.txt file which describes where a search engine robot should go, or not go.

A "nofollow" tag is read by search engines slightly differently as described in the following table:

Note: In 2005 Google announced that the use of the "nofollow" tag would have no bearing on the link target's PageRank.