The nofollow tag was originally created to deter spam comments from making an impact on comment sections of blogs, advertisements, paid links, and more.
Links are a key ranking factor for search engines. SEO relies partly on having content that earns links. However, not all links pass value and authority signals. Some black hat link building tactics drove the need for a way webmasters and site editors could show that they didn't approve of links, didn't have editorial control, or otherwise didn't want links on their sites passing "link juice" — hence, the nofollow tag.
Nofollowed links are links that have the HTML rel attribute that tells a web crawler to not follow that specific link. Essentially, this means that the site or document it links to is not (fully) endorsed. Nofollow tags haven't always been a part of SEO. In fact, the nofollow tag was created in 2005 to help Google find a better way to prevent comment spam.
Spam comments became increasingly popular along with the rise of blogs. Spammers would leave links pointing back to their site in the comment section of another blog, starting a trend that would eventually spin out of control. This doesn’t sound like it would be a big deal but, actually caused a variety of issues — one being that the spammer’s sites would start to rank well.
So how does the link change? A nofollow tag is written in HTML format and goes from this:
Visit my <a href="http://www.examplewebsite.com/">Example link text</a> site.
Visit my <a href="http://www.examplewebsite.com/” rel="nofollow">Example link text</a> site.
Adding the “rel” attribute (short for relationship) allows you to qualify your outbound links to Google. Links marked with these rel attributes typically won’t be followed. However, the linked pages may still be found in different ways, such as sitemaps or links from other sites, and thus they may still be crawled.
These attributes are used only in <a> elements. The effects of the nofollow attribute can also be achieved by editing your robots meta tag. If you need to prevent Google from following a link to a page on your own site, use the robots.txt Disallow rule.
Nofollow links aren’t just for blogs. In fact, it’s encouraged to use the rel=”nofollow” attribute anywhere that users can add their own comments. This includes:
There has been misunderstanding and misinformation about the nofollow tag from the beginning. Many sites will mark all outbound links as nofollow, site editors will nofollow business links, blog owners will only “follow” your link if you pay, and some sites even nofollow internal links to their own content. This is why it’s important people are aware of the risks that the nofollow attribute is supposed to mitigate, and when they should or should not use it.
To help clear up any misunderstandings, a new set of tags was launched in 2019 — User Generated Content (UGC) and Sponsored Link. These tags now exist as an alternative to the nofollow tag. UGC can be applied to links in comments, or across whole sites like Reddit and Quora to show how the content is not subject to editorial control, and should not be considered as a normal link in passing authority or signaling relevance.
Anyone can check to see if a link is nofollowed.
Luckily, there are free tools and browser extensions that can be downloaded that will check for these links automatically. Here are a few to choose from:
Backlinks are essential to ranking pages and domains in organic search. However, if a link building campaign yields some nofollowed links, it can be hard to know if they have a beneficial impact, or a neutral one. It depends on who you ask. Some say they aren’t beneficial at all. At least they don’t have a negative impact — any organic backlink profile will naturally include at least some nofollowed links. However, although nofollow links may have a diluted impact, they can still be used to support SEO:
“Did you know that number 1 ranked web pages on Google have an average of about 20%-40% nofollow links pointing to that page? Sometimes it is even higher. 3 out of 10 links are nofollow links. Think about that. The link attribute that was supposed to totally kill all SEO effects, shows up a third of the time in number 1 ranked sites,” says Adam White in an article about nofollow links actually being good for SEO.
By default, links are followed. There is no “follow” tag that needs to be added for links to be crawled or to pass authority. Adding rel=”nofollow” to a link will signal to search engines that you don’t want them to actually crawl the link, and they generally will pass no link authority to the website you link to. Any link without the rel=”nofollow” tag will be crawled and indexed as usual.