The rel=”nofollow” tag is one of the simplest HTML tags around, and one that’s crucial to understand if you’re doing SEO. How nofollowed links came to be, how they help with SEO, and how using them correctly can protect your site from a dreaded Google penalty.
What are nofollow links?
Nofollowed links are hyperlinks with a rel=“nofollow” tag.
These links do not influence the search engine rankings of the destination URL because Google does not transfer PageRank or anchor text across them. In fact, Google doesn’t even crawl nofollowed links.
Nofollow vs. follow links
Followed and nofollowed links look identical to the average web user.
The blue text in this sentence is a followed link. The blue text in this sentence is a nofollowed link. The difference between the two is apparent only when you dig into the HTML code.
&lt;a href=&quot;https://www.cowanmarketing.com&quot;&gt;blue text&lt;/a&gt;
&lt;a href=&quot;https://www.cowanmarketing.com&quot; rel=&quot;nofollow&quot;&gt;blue text&lt;/a&gt;
The HTML is identical except for the addition of the rel=”nofollow” tag.
It’s possible to nofollow all links on a webpage by placing a robots meta tag with the value “nofollow” in the header. However, the nofollow tag is more commonly used as it allows one to nofollow some links on the page while leaving others followed.
2009: Google combats PageRank sculpting
PageRank flows around a website via internal links (links from one page on the site to another).
For example, some of this article’s PageRank flows to the other pages on our site via hyperlinks like this one. In general, higher PageRank equates to higher rankings.
However, PageRank only gets transferred via followed links, not nofollowed links.
That’s always been the case, but the way PageRank gets shared between the followed links on a page has changed over the years.
Before 2009, it worked like this:
If you had three links on a page and one of them was nofollowed, then the total PageRank was split between the two followed links.
Unfortunately, some people started taking advantage of this technicality to manipulate rankings by sculpting the flow of PageRank around their sites.
In other words, they’d nofollow links to their unimportant pages to allow for the maximum transference of PageRank to their “money” pages.
Google announced changes to nip this practice in the bud in 2009:
So what happens when you have a page with “ten PageRank points” and ten outgoing links, and five of those links are nofollowed? […] Originally, the five links without nofollow would have flowed two points of PageRank each […] More than a year ago, Google changed how the PageRank flows so that the five links without nofollow would flow one point of PageRank each.
Here’s an illustration of the before and after:
While PageRank sculpting is no longer a thing, “nofollowing” some internal links can help with crawl prioritization because Google doesn’t crawl nofollow links.
Search engine robots can’t sign in or register as a member on your forum, so there’s no reason to invite Googlebot to follow “register here” or “sign in” links. Using nofollow on these links enables Googlebot to crawl other pages you’d prefer to see in Google’s index.
However, this is a somewhat advanced topic, so I won’t go any deeper into that here.