Information Architecture
October 2nd 2018

What are Topic Clusters?

Your rankings are suffering, and you’re not getting the traffic to which you’ve been accustomed. You’ve optimized your pages using every trick in the book. You’ve gone after less competitive keywords, and still, nothing works.

Welcome to the world of topic clusters. The not so secret weapon that content strategists are using to lay claim to high rankings in search engine results pages.

What Are Topic Clusters?

A topic cluster is multiple pieces of content that are grouped by a shared topic and related subtopics. As a whole, these pages offer comprehensive coverage of a specific subject. That enables visitors to satisfy their search query while visiting your site.

Take, for example, a website with the main topic of appliances. It could have detailed content discussing kitchen appliances like blenders and food processors.

Since the introduction of Google Hummingbird in 2013, content marketing has fundamentally changed. Gone is the emphasis on keywords and pages. In its place, we have pillar pages, content clusters, and subtopics. All this combines to create websites with high topical authority. It’s the type that Google favors.

Before Hummingbird, inbound marketing was relatively simple. The typical content strategy consisted of finding popular search queries. Then you would create blog posts to match each of those keyword phrases.

Each page was optimized to rank for a specific keyword. The intense focus at the page level meant little attention was paid to the site as a whole.

Eventually, large sites found themselves with many pages of similar content. They were targeting so many keywords they couldn’t keep track! The content that was unique tended to be shallow. It lacked the depth necessary to satisfy search intent.

It’s what content marketers often refer to as ‘thin content.’

Search engines are getting better at determining expertise. So smart content strategists are shifting the focus from keywords to topic clusters. They’re using topic clusters to organize their content and build authority.

In the current environment, a content plan that does not use this tactic is at a severe disadvantage. It’s too difficult for low authority sites to achieve meaningful rankings. To give you an idea of how a plan would look, here’s a post on building a content plan with topic clusters.

Now to be fair, topic clusters aren’t exactly new. In fact, WordPress users are familiar with a related concept known as ‘category.’

Categories and topic clusters are very similar. While every category is a topic cluster, every topic cluster is not necessarily a category. On our appliance website, we may choose to make a category for ‘kitchen appliances,’ while keeping blenders and food processors as clusters.

There are no hard and fast rules when it comes to organizing a website using topic clusters. Usually, a group will have at least four pieces of content, but that’s a suggestion. Your content plan may call for multiple pieces of content in a topic cluster. But you can publish them one at a time according to your schedule.

Existing sites can also take advantage of topic clusters. To restructure an existing site, you’ll first need to conduct a content audit. List every blog post and group entries into topics and subtopics. Eventually, you’ll end up with clusters of content which you will link together at a later stage.

Real-world Topic Clusters

So far, the conversation has all been theoretical. Let’s take a look at some real live cases to see how others work topic clusters into their content strategy.

My favorite is Chaos Monkey Guide for Engineers. This nicely designed pillar page is a complete how-to about Chaos Monkey. Included in this page is a summary of each chapter of supporting content with links to these pages. It’s well-structured and easy-to scan, making it ideal for both search engines and humans!

screen shot of pillar page on

Wikipedia, with 45+ million well-organized pages, it is definitely the king of clustering. Their pages make extensive use of in-content links to connect related subjects. Thus it can be a little difficult to see how subject matter is structured. Occasionally you’ll run across a template like the one shown here on Content Marketing.

We can see that this page is part of a series of pages covering the topic of Internet Marketing. Notice that some subtopics also have their own topical clusters. Examining the links on individual pages, you’ll notice that they’re interwoven very much like a spider’s web.

A site doesn’t have to be the size of Wikipedia to take advantage of clustered content. This far smaller site on canal barge cruising also groups content into a limited form of clustering.

In this case, the link structure is more tree-shaped. The main topic “barge cruise areas in Europe” links out to various pages detailing cruises in different European countries. However, unlike the Wikipedia example, subtopic pages don’t link back to the main topic page.

There are no hard and fast rules about interlinking related pages. Linking doesn’t have to be reciprocal, but if two pages are related, it makes sense to link in this manner. Content management systems that make use of categories enable quick and easy clustering of related blog posts and pages. It’s not the best way of organizing relevant content, but it’s better than nothing.

Look at this example from an audio retailer. Some posts have been classified into the “home stereo systems” category. A category page displays all matching content along with the linked title, author, and summary.

This page is most likely created programmatically. As a result, there is little in the way of content on this topic page. In a case like this, it’s a good idea to interlink the related content to establish a tight relationship between subtopics.

When topics are clustered together coherently, Google not only recognizes your topical authority. It may reward you with an enhanced listing as seen in this search result.

In this SERP both The Wire Cutter and Consumer Reports have additional listings. It appears they are based on the way each has organized their site into topics and subtopics. This brings us to a fundamental reason for using topic clusters.

The SEO Impact of Clusters Of Content

Correctly implemented, topic clusters can have a significant impact on SERPs in two ways. First, there’s an increase in site authority and overall page ranking that is conferred to sites that comprehensively cover their chosen topic(s).

Although we’re just speculating, it does make sense. Google’s stated intent is to provide relevant results that match search intent. Making use of topic clusters to thoroughly cover a subject tips the odds of achieving a high ranking in your favor.

More obvious is the type of result we saw in the example above. Sites with well organized and large topic clusters are more likely to receive enhanced listings.

Consequently, on-page SEO efforts are becoming increasingly more important. That’s good news for both you and your audience! In fact, the focus on improving user experience is widely recognized as an essential SEO strategy.

Topic clusters are useful regardless of your site’s size. If you want your site to grow, get started using topic clusters today. Of course, the more content on your site, the more significant the potential impact of proper organization. In theory, more content means greater possible coverage of a topic. This assumes that each post is in fact in-depth content.

Creating topic clusters isn’t tricky. You need a few pieces of related content interlinked using relevant keywords. You’ll also require a main page to tie all that content together by linking to every post discussing a pertaining subtopic. This page is frequently referred to as pillar content.

The Role of Pillar Content

As the main page for a particular topic, pillar pages play an essential role in the use of topic clusters. The pillar page is typically long-form content that provides exhaustive coverage of the main issue and links to other pages offering detailed commentary on a specific subtopic. A pillar page, along with its corresponding subtopic posts together make up a topic cluster. It’s this structure, along with the content itself, that gives the pillar page the ability to rank for competitive search terms.

Making the switch to pillar pieces and topic clusters requires a shift in thinking. You need to accept that days of writing posts to rank for specific keywords are over.

Topic is the new keyword.

However, making this shift can be made more comfortable, with the right approach. Start by looking at your existing content and see how it can be grouped together into topics. Check for pages that address a central theme and use them as pillar pages.

Update and improve those pillar pages as necessary. Make sure to link out to those supporting pages. Remember to link between supporting subtopic pages as well.

Start thinking strategically when planning new posts. Look at how you can provide extensive coverage of a particular topic, over multiple posts.

Don’t think of them as a series of posts. Instead, consider them as a cluster of content.

One post covers the main topic while other posts drill down into the details. Then link them together as you publish.

Topic clusters can be powerful when implemented correctly. So start small. Organize your existing content and look for potential pillar pages. Improve those as required and link it all together. Then move onto creating topic clusters as part of your regular publishing activities.

Stephen Jeske

Written by Stephen Jeske stephenjeske