In order to understand what a nofollow attribute is you must understand how search engines determine page authority. If you have a website where your home page links to 10 internal pages on your own site and to 5 external pages on other sites, this means you have 15 outbound links. When someone links to your home page, this gives you what is known as an inbound link. If you have 30 inbound links (which you have no control over), then in total you have 45 links associated with your website’s home page. When search engine crawlers index your site, they follow all 45 of these links and, depending on the web authority (PageRank and other factors) of those pages, they pass link juice to your site to determine its search ranking. Your page also passes link juice to all 45 of these links. Transferring link juice is a two way street, unless you block the traffic with a nofollow link attribute.

Definition of a NoFollow Attribute:

Nofollow is a link attribute represented as rel=”nofollow” that is placed within the anchor tags (<a>) on a site. A nofollow attribute indicates that the link within the anchor tag must not be followed by the search engines.

If your anchor text is linked in the HTML in the following manner:

<a href=www.example.com><em>Anchor Text</em></a>

You can nofollow the link like this:

<a href=www.example.com rel=”nofollow”><em>Anchor Text</em></a>

Adding the nofollow attribute indicates to the search engine crawlers that these links must not participate in determining the search engine ranking of your page. However, you do not stop search engines from indexing the page by adding a nofollow attribute. These pages will still get indexed by search engines if they have other links connected to it without nofollow or if they are included in a sitemap, they just will not get link equity from your site.

Reasons to Use a NoFollow Attribute:

  • To Avoid Spam: If your page is linked to a spammy website or if you link to a blog that receives spammy comments and irrelevant links, you would want that link to be nofollowed.

  • To Avoid Paid Links: If you are keen on impressing the Google bots (Google garners the largest share of the search industry so it is important to follow their rules), you must not allow paid links to pass link juice to your site. This is a clear violation of Google’s quality guidelines. In fact, Google has provided a reporting system for sites that are found to increase their PageRank using paid links. So, it is best to nofollow paid links on your page. Paid links can take the form of banner advertisements, text links on your site or paid links that are literally there to acquire a higher PageRank.

Nofollow links are used in many forum platforms and blogs where public comments are allowed. Some CMS blogging platforms have integrated this attribute in their blog commenting code, the biggest example being WordPress.

Nofollow Linkbuilding:

Do not work hard to build links with other sites that use the nofollow attribute. These will serve no purpose in terms of passing link juice to help enhance your site’s SEO. However, if you get an opportunity to add a link to a site that is nofollowed but very popular, you could link to it to expose your site to their audience. For instance, if you can drop a link on a famous forum in your niche topic that is nofollowed, you will be able to earn web traffic from people that visit the forum, so it could be worth it even without the benefit of link juice.

Sometimes it is beneficial to have a few nofollow links in your site’s link profile to show that your site is earning links naturally. To check if a website is nofollow you can view their source code (open a web page and press Ctrl+U in Firefox, or right click and view page source in Chrome) and find the word nofollow (by pressing Ctrl+F and typing nofollow), as shown in the screenshot below:

Find nofollow links in the source code of a web page

Firefox users can download this plugin to detect nofollow and dofollow links.

NOTE: Dofollow is not a link attribute; it is just a term indicating that a link is not nofollow.