How many internal links is too many? Can I link with total abandon? It’s a question we’ve all probably asked ourselves before. And while Google doesn’t penalize you for linking to other pages on your site, it’s important to consider other factors as well.

Whenever someone lands on your website, whether they’re a user, a reader, or a potential customer, they’re looking for information. The core of the customer experience centers on how you present that information to them and how easy it is for them to find it.

Proper internal linking ensures that this experience is the best it can be. Think about it like you’re building a library for them to browse through: everything is organized to facilitate research.

But internal linking is more than that as well. It’s a signal to search engines that your content is a comprehensive and authoritative resource on the topics, keywords, and queries that certain searchers are looking for. When you understand how search engines work, linking complementary articles together can help strengthen their position in the SERP across the board. It showcases quality and authority on a particular topic that helps you rank higher, build backlinks, and tap into the compounding value of keyword growth.

We wanted to see just how much internal linking can impact these factors. And what better way than to test out the content on our own blog. So we put together an experiment to learn more about how important internal linking is for SEO and how it affects the reader’s experience.

How do inbound and outbound internal links affect our rankings?

Internal Linking Experiment: Our Goals and Methodologies

The goal for this experiment was to see how updating the internal link profile of an existing article affected its SEO value. To test this, we chose two posts that were performing well but could potentially do better in the SERP. In one article, we updated links from relevant posts across the SpyFu blog to direct readers to that article. In the other, we included a number of outbound links to other relevant content from the blog.

In both, we were careful to choose anchor text that made sense for both the target article and the existing written content. More on that later.

Here are the two articles we chose:

We wanted to see how the different internal linking strategies affected ranking for the target articles. Would the article with the new inbound links rank better? Or would the article that linked out to other relevant content perform better?

At the beginning of the test, “How to Improve Google Rankings: 10 Tried and Tested Ways” had been published for about one year, and “The Beginner's Guide to Rich Snippets” for only one day. The reason for this was so we could track how internal linking affected an established piece of content as well as a brand-new one.

We decided to look at a few key metrics for each article:

  • Backlinks
  • Total keywords
  • Ranking position for target keyword
  • Overall traffic

Once we placed the requisite internal links for each article, we tracked how these metrics changed over a three-month period, with the idea that we could check back on the progress after six months, one year, etc. Here are the articles we updated to direct readers to “How to Improve Google Rankings: 10 Tried and Tested Ways,” including the anchor text we used:

The 12 updated internal links for “How to Improve Google Rankings: 10 Tried and Tested Ways”

And here are the internal links we added from “The Beginner's Guide to Rich Snippets ”to other articles on our blog.

The 10 updated internal links from “The Beginner's Guide to Rich Snippets ” to other content

At the beginning of the test, this is where each article stood in terms of our key metrics:

With that baseline in place, we could easily track how each article changed over the coming months. So we got ourselves comfy, and we waited.After two months, we took a look at these metrics again:

The “How to Improve Google Rankings: 10 Tried and Tested Ways” article showed a 28% increase in total inbound backlinks, a 129% jump in total keywords, and a +2 ranking change for our target keyword.

“The Beginner's Guide to Rich Snippets” showed no increase in total backlinks, and we saw a 12%  increase in total keywords and a +1 ranking change for our target keyword.

At first glance, we see that the article that garnered more direct links from existing content had more positive change across the board. While the article with outbound links saw some positive change, it wasn’t to the same extent.

We want to track how these metrics continue to evolve over the next six months, but there are already a few interesting takeaways for us to unpack so far.

Let’s dive in!

Inbound Internal Linking Helps Rankings Grow

When you increase the number of internal links directed to a specific page, it can boost the total number of keywords you rank for, as well as your target keyword rank. This is a really powerful tactic for increasing the overall strength of your SEO and is the core driver behind the topic cluster/hub-and-spoke model.

Just keep in mind that you’re not only creating random links between pages here; the content you link to has to be relevant and provide added value to the reader. You also need to make sure you don’t overwhelm readers with too many links. Leaning on our library metaphor from earlier, whenever you’re thinking about adding another internal link, you’re shelving another book in the same stack.

When you do this correctly, you’ll see an increase in total keyword rankings for your article and a positive movement in your target keyword rank.

Total Keywords

Both articles we tested had an increase in the number of total keywords they ranked for—12% for “The Beginner's Guide to Rich Snippets” and a whopping 129% increase for “How to Improve Google Rankings: 10 Tried and Tested Ways.” That said, the article where we placed inbound links directly did significantly better in that respect. A 129% growth in total keywords over two months is, frankly, amazing.

Total keyword growth for “How to Improve Google Rankings: 10 Tried and Tested Ways” via ahrefs

And the “The Beginner's Guide to Rich Snippets” article started seeing these increases immediately after the start of our test. Within days, we started to see an upward trajectory that continues to trend in that direction. That's really impressive for an established article. When your content ranks for more total keywords, including long-tail variants of your target keyword, it shows search engines how relevant your content is.

This kind of increase not only makes the article more visible for searchers using 128 different keywords related to Google rankings but also gives search engine crawlers a more efficient path to find the page and bring it back for indexing.

Whenever a crawler lands on your website, it’s looking specifically for new and updated information. So increasing the number of connections between similar topics through internal linking will signal to the bots that you’ve made changes to the page.

Those crawlers will take this information back to the search engine, which then categorizes the relationships between different pieces of content and makes changes to their ranking algorithms that push your content further up in the SERP. This makes your content more available for a number of different searches and will increase total organic traffic as well.

Traffic growth for “How to Improve Google Rankings: 10 Tried and Tested Ways” after updating internal link profile.

We see an almost 100% jump in unique page views that coincides with the start date of our test. For an established piece of content, this bump can help rejuvenate readership and increase traffic without requiring the amount of work that would go into a full article refresh.

The “The Beginner's Guide to Rich Snippets” article, while seeing a 12% increase in total keywords, didn't experience this same kind of traffic growth.

Traffic growth for “The Beginner's Guide to Rich Snippets” after updating outbound internal link profile

This makes sense. When we updated the Google-rankings article, we increased the potential number of people who could find the article on our blog and in the SERP. Including outbound links in the “Rich Snippets” article increased its visibility to search engine crawlers but not to the readers of our blog. We can attribute the slight traffic increase that week to normal fluctuations.

Target Keyword

Both articles we tested saw an increase in rank for their target keyword as well. While it’s only a one or two position change, this is likely due to a combined impact of increasing both the internal links and the total keywords, both of which being positive signals for search engines.

“The Beginner's Guide to Rich Snippets” is currently in a more valuable position in the SERP, with its movement from 6 to 5. While it's said that the first position in Google gets the lion's share of the clicks, higher rankings can also increase the potential for landing an important search feature.

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Organic keyword ranking for “The Beginner's Guide to Rich Snippets” via ahrefs

"How to Improve Google Rankings: 10 Tried and Tested Ways” also saw positive movement toward the first page of the SERP, but it was competing for a much more difficult keyword. The how to improve google ranking long-tail keyword has a difficultly of 70 as opposed to rich snippets examples, which is only a 41.

Screen Shot 2020-05-14 at 3.31.22 PM.png

In the next three to six months, we will likely see additional increases to these rankings based on the overall positive movement of the content so far. But it’s important to note that these position changes aren’t as significant as the increase in total keywords. When it comes to internal linking, it’s more likely that you’ll increase the total number of keywords an article ranks for by creating relevant anchor text.

“The Beginner's Guide to Rich Snippets” doesn't benefit from this tactic because it only links out to other articles. Keep that in mind while you’re thinking about your own internal linking updates.

Making additional connections between existing articles is always a good idea, but inbound links seem to have a more direct positive impact on SEO.

Anchor Text Signals Relevancy for Readers and Search Engines

In preparing for our test, we thought a lot about what anchor text to use for each article. Whenever you link to an existing piece of content, your job is to tell readers and search engines what the corresponding article content is all about. Not only is it an opportunity to communicate the value of that article to readers, it’s a way to include a long-tail variation of the articles target keyword.

One of the benefits of increasing the total number of internal links to your content is that you have the ability tailor this anchor text to be the best that it can be. Great anchor text balances how it signals relevancy to search engines as well as improving the experience for readers on the page.

If you take a look at the anchor text we chose for the “How to Improve Google Rankings: 10 Tried and Tested Ways,” you can see how each relates to the content of the article.

Internal links for “How to Improve Google Rankings: 10 Tried and Tested Ways”

Each phrase tells the reader what they can expect to learn about by clicking the link. It’s that kind of relevance that helps boost the rankings of this article. Everything is related to the content and relevant for search engine crawlers. The same is not true for the anchor text in “The Beginner's Guide to Rich Snippets.”

Internal links for “The Beginner's Guide to Rich Snippets" articles

While all the anchor text is relevant to the article it links out to, it’s not directly relevant to rich snippets. As a result, we didn’t see the same increase in total keywords that we did for the Google-rankings article. It will be interesting to see how the inbound traffic increases to the articles linked to from “The Beginner's Guide to Rich Snippets” article. Right now, there weren't any significant increases to the other articles we linked to.

When you’re thinking about how to maximize the SEO impact of your anchor text, it all comes back to relevancy. You want to make sure that each link you include is germane to the content you’re directing visitors to.

It’s a good idea to see if you can fit in any long-tail variations of your target keyword as well. For “How to Improve Google Rankings: 10 Tried and Tested Ways,” the anchor text we used all revolved around “rankings” and “improving” them, so it helped both readers and web crawlers better understand what the content we were linking to was all about.

Looking at how each article gained backlinks over the past two months, it’s easy to see that increasing the number of inbound links to a post is the better strategy. “How to Improve Google Rankings: 10 Tried and Tested Ways” saw an increase in its backlink profile from 114 to 146. “The Beginner's Guide to Rich Snippets” saw no increase whatsoever. This makes sense if you consider how each article changed as a result of our test.

  • “How to Improve Google Rankings: 10 Tried and Tested Ways” became more visible to readers and the SERP because we increased the number of connections to it from other areas of the site.
  • “The Beginner's Guide to Rich Snippets” also increased in the number of connections it had with our site, but visibility didn't increase.

As the Google-rankings article gained inbound links as a part of the test, there were more arrows pointing to the content. Combine that with the already solid backlink profile it had and it’s easy to see how these changes made the article easier to crawl.

The rich snippets article gained outbound links, so the arrows were pointing away from the content. While still valuable for connecting it with other pieces of content on our blog, we weren’t actively telling readers and search engines that this was a piece of important content.

“How to Improve Google Rankings: 10 Tried and Tested Ways” is also ToFu content and therefore appeals to a larger audience. “The Beginner's Guide to Rich Snippets,” while targeted at beginners, is still a concept that might not be immediately valuable to as many people as the rankings article.

While these results weren’t totally unexpected, we’re eager to see how the test results continue to evolve as we give the articles more time to gain traction in the SERP. When you’re trying to make a meaningful impact on the SEO value of your content, it’s important to remember that it takes time to understand all of the results.

Content Marketing Is a Long Game

This test provided us with a number of beneficial insights into how valuable internal linking can be for content on your blog. When you elevate the perceived value of a piece of content by pointing more links to it from other areas of your blog, you’re showing both readers and search engines that it’s worth their time.

It will be really interesting to see how these metrics change over the coming months. Building authority for your brand and SEO value for your content is never a quick solution, so we will be checking in on the results and will make updates to this article when any new takeaways arise.