The Nofollow attribute is a powerful SEO tool with some legitimate applications, but it’s often frequently misunderstood and misused. How does it work and how should you use it properly?
Google and Links as Votes
The way Google works is largely based on links. In the beginning, it was based entirely on links. Everything else has been added on top, to make the algorithm a little more robust, a little more discerning and a little more detailed. The core functionality of links, however, remains the same.
Essentially, when you link to a site, you’re putting in a vote of confidence for that site. You’re saying to your users and to Google that the destination site is worth visiting and viewing.
PageRank is an accumulation of how many other sites have voted for your site. When links count as votes, more links mean more votes, and more votes boost your PageRank.
To make PageRank more than just a popularity contest that favors old, large sites, it’s also used to weigh the votes. A site with a high PageRank has a vote that counts for more than a site with low PageRank. Spam sites, meanwhile, have a low or negative PageRank, meaning their vote is valueless or potentially detrimental.
Meanwhile, when you vote for a site via link, some of your PageRank passes on to that site. That site accumulates that PageRank and adds it to its own total. When you link to several sites in a single page, your outgoing PageRank is split amongst those sites.
This opens up an issue, however. When every link you make is treated as a vote of confidence, you don’t necessarily want to vote for some of the sites you may otherwise link to. Google wants to encourage links, to build a better sense of how the Internet relates to itself. Therefore, Google needed to come up with a system that allows you to link to a site without your vote counting.
Dofollow and Nofollow
All of the above is how Dofollow links act. These are normal links, the way they have always existed on the Internet. The alternative is a Nofollow link.
When Nofollow was first introduced, it essentially made a link not count, in a number of ways. The link still existed, and Google could still use it to discover new pages and crawl those pages. All other functionality was cut off. A Nofollow link does not count as a vote of value in the destination site. This allows you to safely link to sites you don’t know, sites you don’t trust or sites you know are spam.
Further, a Nofollow link would cut off the passing of PageRank. If you had three links outgoing, and made two of them Nofollow, the third would gain all of the beneficial PageRank. This led to issues, and was changed.
Nofollow for PageRank Sculpting
The progess that came up then was called PageRank sculpting. Essentially, a webmaster would use Nofollow links to funnel PageRank through to specific links on pages otherwise full of links. This allowed them to accumulate and distribute PageRank in ways that were as beneficial as possible to the site, but artificial.
Google’s change divided up PageRank amongst all possible links, and simply kept it from passing along Nofollowed links. Before, having three links on the page, only one followed, would pass all of the PageRank available along that one link. Now, those three links divide PageRank equally, but nothing goes to the two Nofollow links. The followed link only receives a third of the PageRank, and the other two thirds goes nowhere. It’s not hoarded, but neither is it passed on.
Nofollow for Hiding Pages
One other incorrect use of Nofollow links is the idea of hiding a page from Google by making all links that point to it Nofollowed. This is based on a misunderstanding of how Nofollow works. Above, it was mentioned that Nofollow links are still crawled and the page at the destination still indexed. This has not changed.
The attribute necessary to hide a page from Google is the NoIndex attribute. This, added to a link, means that Google won’t crawl the destination page. You can use NoIndex attributes to hide a page, and in some cases you should. Most of the time, however, it’s a better idea to use the meta NoIndex attribute in the header of the page itself, rather than on links pointing to it. All it would take would be a single link without NoIndex to reveal the page, otherwise.
Legitimate Uses for Nofolow Links
With so many ways to use Nofollow incorrectly, what is the proper use? Think back once more to the idea of votes. Very often, you may want to link to a site without that site benefitting from the link. Linking to a spam site as an example, for instance, would not be a vote of confidence. That’s a link you would want to Nofollow.
Another example is links you don’t control. Prime among these are links in comments. Any user can come in and post a link in your blog comments, and you gain nothing from allowing your PageRank to be distributed to those links. This is why spammers frequently target unmoderated comments; sometimes they can bring value to the spam site. Nofollowing comment links isn’t a substitute for moderation, but it can keep you from accidentally passing value to a spam site.
Using Nofollow Internally
So, back to the original question. Should you add the Nofollow attribute to your internal links? Think back to what Nofollow does. It doesn’t stop Google from indexing a page, so you couldn’t use it to hide a page. It stops PageRank from passing, but passing PageRank in between your own internal pages doesn’t matter. Therefore, a Nofollow link between internal pages does nothing. It neither helps nor hinders your site whatsoever. There’s no reason to add it in, and it does need to be added in manually if you’re going to add it at all.