That link actually looks like this in HTML:
a href=”http://support.google.com/webmasters/bin/answer.py?hl=en&answer=96569″ target=”_blank” rel=”nofollow”>Google Webmaster Tools on Nofollows
The value ostensibly tells search engines not to use a link when formulating the host website’s overall search engine ranking.
Nofollows were often used to control page rank from 2005-2009, but since Google’s Matt Cutts announced that the search engine would interpret nofollow links differently. Since then, we’ve seen that Google still uses rel=”nofollow” links as part of their formula for page rank, but the search engine does not index the linked page. Other search engines follow the links, and Yahoo! even indexes pages with the nofollow attribute.
I believe that this change is detrimental to the health of the Internet, since page developers have one less tool available for link juice sculpting. Nevertheless, in order to use rel=”nofollow” correctly, we need to understand how search engines use the attribute and choose an appropriate tactic. Ultimately, the number of links on each page of a website count towards the total page rank–nofollow or not–so webmasters might need to do some regular housecleaning to get the best possible page rank.
Given the relatively recent changes to the value, the proper way to use nofollow is as a means of combating spam and rewarding high-quality content among your website’s regular readers. I typically recommend making rel=”nofollow” a default inclusion on all reader-submitted links. As members of your website spend time on your site and contribute relevant, helpful posts, you can remove the nofollow attribute from their outgoing links.
Just to be clear, you shouldn’t use rel=”nofollow” just to sculpt your website for Google, and you can’t use the value as an end-all attribute tag to fight spam. I still recommend checking for spam links and deleting them as necessary, since every link on your site could conceivably count against your PageRank.