I teach Digital Marketing at some Business Schools. In one of my recent classes, I was discussing SEO, or Search Engine Optimisation (the process by which you aim to have your site rank high on the Organic Search Results page of Search Engines).

SEO is a complex topic encompassing technical, on-page and off-page tactics. As I was explaining these concepts, it was interesting to find that the topic that generated the maximum number of questions was the role of ‘nofollow’ in links.

As I reflect on this now, a few days after the session, I can understand why this might be a difficult topic to grasp, especially for people who are new to this field. Here is an attempt to explain this further.

As many people know, links are a very important signal of a site or page’s popularity. And popularity, in addition to relevance, are important factors (out of hundreds) that influence a page’s ranking on Search Results Pages. The key thing to note is that not all links are equal. Links that come in from another page (or domain) that already ranks high and is considered as an authority on a topic carries greater value than a link from a relatively obscure site.

A simple way to think about this is that typically, your home page would be the highest ranking or most important page in your web site. And, therefore, any links from your home page would carry more value than links from a page buried deep within your site.

Let’s assume that you have a page on your website (not your homepage) that you would like to rank higher on Search. By linking to this page from your most important page – your home page – you are signalling to Google that this page is important enough to be linked from the home page. Let’s assume that your home page has a Page authority score of 100. If there are a total of 20 links to other pages on your site, then each of these 20 pages would get an authority score of 5 (100/20). Now, not all of those pages might be equally important to you from a SEO perspective. In fact, some of these links might also be pointing to pages on other domains that are not on your own. In such cases, you are passing on some of your valuable authority to those external domains as well.

This is where the role of ‘nofollow’ comes in. By including this tag in your html link, you are signalling to the Search Engine that the link is not important enough for you to be passing on your valuable authority to. This does not mean that the link will not be discovered or ranked by the Search Engine, just that the Search Engine would not assign any part of your domain or page authority to the linked page.

So, in the example above, if you mark 10 of the 20 links from your home page as ‘nofollow’, each of the remaining pages would get an authority score of 10 (100/(20-10)). This is twice the authority compared to the previous setting. And hence, each of those 10 pages would now have a better chance of ranking higher on the Organic Search Results page of Search Engines.

Interestingly, just a few days after my session, Google made a key change to how it considers ‘nofollow’ links. While previously, Google would not count any link with this attribute as a signal to use within their algorithms, they have recently announced that this would change from March 2020. Now, ‘nofollow’ will be considered as a ‘hint’ which they would use along with other signals to better understand how to analyse and use links within their algorithms.

I do not know yet how this change might affect the rankings of pages. This is something that SEO practitioners would have to watch out for.

I hope this helps understand the ‘nofollow’ attribute better. If you have any questions or comments, please do post below.