In 2005 Google announced the rel=nofollow link attribute. They said that using it would make Google ignore the link. Googlebot would not pass PageRank across the link. For search engine ranking purposes, it was like the link wasn't even in the page. The purpose of nofollow would be to mark links that could be spammy such as links in user generated content.
That lead many webmasters to see nofollow as a tool to control link juice on internal links within their own site. The thinking was that adding nofollow to an internal link would cause Google to pass link juice only to the important internal links on the page. It turns out that thinking was misguided.
Nofollow doesn't cause links to be ignored
It turns out that Google has never ignored nofollow links. Rather than make the PageRank the link would pass available to the other links on the page, Google simply discards it. This means that using nofollow doesn't send additional PageRank to the other links on a page.
Preserving PageRank internally doesn't help rankings
It also turns out that discarded PageRank to internal links doesn't hurt your SEO. Other types of links such as links to page disallowed by robots.txt effectively discard PageRank. Neither using nofollow nor disallowing with robots.txt seem to hurt the rest of your site as one might expect if PageRank were actually wasted in these cases.
Nofollow is now a "hint"
Google recently announced that nofollow is now treated as a "hint" rather than a directive. Now Google may choose to ignore the nofollow and pass link juice across the link anyway.
In conclusion
Nofollow is not useful for directing the flow of PageRank internally on your own site.
This article was written as part of a series about SEO myths.
