Updated: May 25, 2012
I see a lot of outdated information about the rel nofollow tag. Particularly a lot of advice to use it in page rank sculpting. That might have been useful at one point, but it hasn’t been for over a year now.
The nofollow tag is a tag you can add to a href link to tell Google not to pass page rank to the link. It is typically used for comments on a blog (to discourage comment spam) and for sponsored links. By adding this tag to your href HTML code you are telling Google, I’m not sure I trust this site and I don’t want to pass my link juice over to it.
Here’s an example.
<a href="http://www.foo.com" rel="nofollow">foo.com</a>
Google expects you to use the nofollow tag on any links that you are being paid for.
SEOs used the nofollow tag to “sculpt” page rank on websites. To understand this, remember that page rank flows down from the home page to the pages that the home page links to. So if you have five links on your home page, then 1/5th of the page rank assigned to the home page flows to each of the pages, and then that 1/5th is then divided out among the links on that sub page. So what if you have a link that shows up on every single page (Iike a “contact us” in the footer) and you are not particularly interested in having that page rank? You rather have other pages get the link juice. So enterprising SEOs used the nofollow tag to keep the page rank from flowing down to these “unimportant” pages (from the SEO perspective) and have it flow to the other pages instead.
Rel nofollow hasn’t worked for page rank sculpting since 2009, when Matt Cutts announced a change on how Google treats rel=nofollow. Essentially the nofollow still prevents page rank from flowing through, but the other followed links no longer gain the extra page rank. So the page rank doesn’t flow through, but it is not reallocated to the followed links and is essentially wasted.
So when you see WordPress SEO guides advising you to add nofollow tags to various links in your theme, keep in mind this might be outdated advice.
There has been a lot of speculation on how Google is treating the nofollow links. The debate continues on this and also on page rank sculpting. Here are my take aways.
Kathy Alice Brown is a SEO expert specializing in Technical SEO and Content. In her spare time she loves to get outside.