In the latest edition of Google’s Webmaster Help Videos, Matt Cutts tackles the question “can nofollow links hurt my website?” We’ll get to his answer, but first, I want to talk a little bit about what nofollow links actually are and how they fit into an SEO strategy.
A regular link to a website is counted as a vote and passes some link-juice to the target, this is the core of traditional SEO. A nofollow link is a way of linking to another site without actually giving it your vote. In theory, a nofollow link doesn’t really boost PageRank, doesn’t help SERPs much, and is pretty much just for navigational purposes. The structure of a nofollow link is about as simple as a regular link, you just add the rel=”nofollow” attribute. Here is an example:
<a href=”http://www.website.com/” rel=”nofollow”>Link Text</a>
So basically, a nofollow link is you telling Google, “Yeah, I’m linking to this, but that doesn’t mean I’m voting for it.”
CAN THEY HURT YOUR SITE?
The short answer to the question is “No.” By and large, nofollow links wont do anything to your site. If you’re going to build links purely for navigational purposes, and they all are nofollowed, it is very, very unlikely that Google is going to penalize you in any way.
Of course, there are always exceptions.
The reality is that nofollow links DO pass on at least a little bit of juice. It’s definitely not as much as an unadulterated link, but they definitely have a little bit of influence. That’s well and good if you’re using them appropriately, but some people aren’t content with that. They want to try and game the system.
Enter the blogspam.
Comments on blogs and other articles are almost always nofollowed. Unfortunately, lots of times, they are also not moderated in any real way. This is why you see (hopefully in your spam folder) strange comments that link to strange sites. There are bots that just crawl the web and plaster these links on every unprotected blog they can find, building a giant network of nofollowed links that will prove beneficial because of the sheer volume. If you’re doing this, Google will find you, and they will penalize you.
Otherwise, build nofollow links to your heart’s content.