We have talked before about using rel=”nofollow” before. Essentially, it is an attribute you add to a link to tell Google that you do not want to pass page juice to the linked page. It’s commonly used for external links to low-quality sites and applied en masse to comment links, but more and more people are starting to apply it to internal links as well. Is it a good idea? We turn to Google’s resident link wizard Matt Cutts for the answer.
The short answer on using rel=nofollow for internal links is “don’t do it.” Matt Cutts advises that PageRank flowing internally, on your own site, is always a good thing. The most common uses are people putting nofollow on the links to forms or login pages. Cutts says that he understands why you would think that these pages don’t need the PageRank, but that it doesn’t really affect things one way or the other. You can use nofollow if you like, but it won’t make a noticeable difference for your site or your rankings. In fact, Matt Cutts says that Google prefers it when you let the Googlebots crawl all of the pages on your site, so using nofollow internally is generally, at best, a waste of your time.
There is one major exception to this rule, and it comes from the comments section. In general, it is always a good idea to have the rel=nofollow attribute applied to all links in your comment section. If you’ve ever run a site before, you’ll understand why. People will try to get in there and post spam, they’ll even get around your captcha to do it. Make your links nofollow so that they’re less likely to try. The more popular your site is, the more careful you have to be.