Having a good organization in the internal linking of a site is a major issue that affects three aspects of SEO: technical SEO, user experience and authority.
1. From a technical point of view, the internal linking will facilitate the task of Google’s robots in crawling and indexing our website. Through internal linking, we can allow Google robots to quickly access the most important pages of our website and thus facilitate their crawling and indexing. It is therefore an essential asset to optimize crawl depth and crawl budget.
2. From a user experience point of view, it is thanks to the internal links that navigation is facilitated to the user and becomes more fluid. How you link your pages and how users understand the website’s navigation will play a major role in the conversion rate.
3. Finally, one of the great advantages of internal linking is that it is also essential for optimizing the authority flow between your pages. Thanks to it, we can distribute the PageRank of a page to the other pages of the site in accordance with our SEO strategy. It is mainly on this aspect that I want to focus on the rest of this article.
In short, PageRank was Google’s official metric for designating the authority of a web page. PageRank was a score that varied between 1 and 10, and the higher the score was, the more authority the page had in the eyes of the famous search engine.
In 2016, Google stopped releasing the PageRank of websites to the public, but this metric is still taken into account by the search engine’s algorithm to evaluate a site’s ranking.
With the end of PageRank, other authority estimation scores developed by different SEO platforms have emerged. Among these metrics, we note the “Domain Authority” of Moz, the “Trust Flow” of Majestic, the “Authority Score” of SemRush, or the “Domain Rating” of Ahrefs.
These metrics are very different from each other and none of them is 100% capable of determining the notoriety of a site in the eyes of Google. That’s why to illustrate the functioning and the impact of internal links on the popularity of a site, we use the general term “authority”.
For Google, the authority of a page is calculated according to the links it receives (internal links and external links). An external link will transfer authority to the page it refers. This concept of distribution of the authority of a link is called link juice.
Let’s illustrate this with an example: Let’s say that Google assigns a score of 6 points of authority to a page A, calculated according to the internal and external links it receives.
Let’s also assume that page A has only 3 internal links to pages B, C, and D. Page A, which has only 3 links, will transfer one third of its authority (6 divided by 3, or 2 authority points) to each of the pages B, C and D.
So we must remember two things:
1. A page distributes its authority equally to the pages it links to (if the link is the same! Read the reasonable surfer theory).
2. The more links a page contains, the more its linkjuice will be diluted, i.e. its power to transfer authority to other pages will be reduced.
If on the same page, we have 100 links, but they all point to the same two url, the distribution of authority will be done between these two pages. Google will only take into account the first link to each page, and ignore the other ones.
Moreover, when we have links pointing to the same page, even if they have different anchors, Google will just take into account the first link and will not even crawl the others.
To illustrate this more clearly, let’s take again the example of page A with an authority score of 6, but this time it has 5 internal links: 3 to page B, 1 to page C and 1 to page D.
Supposing the two links have the same probability of being clicked by a user, the authority distributed by page A will be 2 from the first link that leads to the url /pageB, 2 points from the first link that leads to the url /pageC and 2 points for the link that leads to the url /pageD.
The other links that lead to page B will be totally ignored by Googlebot.
The “nofollow” attribute is a value that can be assigned to the HTML code of a link to inform search engine spiders not to follow that link and thus not to distribute linkjuice to the page it points to.
However, for some time now, Google has been announcing that giving it a “nofollow” indication is not a guarantee that it will not follow the link.
To illustrate the effect of a “nofollow” link in terms of authority, we will take the following example: A home page that makes a “nofollow” link to a page 1, and a “dofollow” link to a page 2. In this case, page 1 will not receive any authority, and page 2 will. However, page 2 will receive less authority than if the link to page 1 did not exist.
In conclusion, the page linked with a “nofollow” link will not receive authority, but the page that links will be able to transfer less authority to other pages. Putting the attribute “nofollow” will not prevent the drainage of authority from the page that makes the internal link.
In my opinion, the only use of “nofollow” links is if you’re linking to a competitor and don’t want to transfer authority to that website, or you don’t want Googlebot to crawl a page.
Canonicals are indications to Google’s robots to not index a page because it’s duplicating another content. They must therefore be taken into account in the SEO strategy.
From an SEO perspective, it is not a good practice to set up links (internal or external) that point to pages with parameters, hashtags or redirects that will then lead the robot to another page.
When you link to a canonicalized url, you ask the search engine robot to make an extra effort that is not necessary.
This also applies to links to pages that are then redirected. If you put internal links to canonicalized urls, the risk is that the search engine does not take into account the indication given by the canonical tag and indexes it anyway, thus creating cannibalization.