Topic clusters are a group of web pages that focus on different aspects of the same topic. They allow you to cover a topic in depth by using each page in the cluster to focus on a particular sub-topic of the main topic.
They help your readers to better understand a topic. But they are also a valuable SEO tool because they help to build your website's authority for particular topics.
In this article I’ll explain:
- What topic clusters are
- Why they help with SEO
- How to create them
Let’s dive in!
1. What Are Topic Clusters?
A topic cluster is a series of interlinked articles or blog posts clustered around a particular topic.
Content clusters are a bit like ‘Category’ pages in WordPress. A category page contains links to all the pages or articles that cover that same category.
The difference between the two is that a category page is simply a list of sub-pages whereas the central page in a topic cluster is usually a lengthy article that gives a broad overview of a particular topic.
Here’s an example:
Let’s say I have a website that deals with outdoor sports.
And on that website, I have a web page that covers rock climbing.
My rock climbing page links to a series of related pages, each of which deals with one of the following topics:
- Ice picks
- Ropes & Cords
- Rappel devices
The rock climbing page and the pages it links to are a content cluster.
You can think of a topic cluster as a central page surrounded by satellite pages.
A key aspect of content clusters is internal linking.
Ideally, every satellite page should contain links to every other page in the content cluster.
2. Topic Clusters and Pillar Posts
The page at the center of content cluster is often referred to as a pillar post.
It’s called a pillar post because it’s usually one of 5 to 10 key content pages that define the focus of a website.
Pillar pages are often long-form content. They typically give a broad overview of a topic.
In my example above, the rock-climbing page is a pillar post.
Pillar posts often have titles such as:
- The Complete Guide to SEO
- Email Marketing – the Definitive Guide
- Guest Posting – Everything You Need to Know
The satellite pages surrounding a pillar post go into particular sub-topics in more detail.
For example, the satellite pages for a pillar post about 'email marketing' might be:
- How to Segment Email Lists for More Opens and Click-Throughs
- 22 Simple Ways to Grow Your Email List
- 13 Best Email Marketing Services
- 7 Email Marketing Metrics You Need to Follow
- How to Create Email Marketing Funnels
Pillar Posts and Satellite Pages
The pillar post on email marketing plus these 5 sub-topic posts would together form a topic cluster.
A key characteristic of a pillar page is that it broadly covers a given topic. In that sense, it acts as a gateway to the pages that cluster around it.
Those satellite pages deal with sub-topics of the main topic. And they cover those sub-topics in much more detail than was possible in the pillar post.
If you’re like me, and many other bloggers, you may not have many pillar pages.
We’ve been so busy chasing long tail keywords that we rarely, if ever, write broadly-focused articles.
After all, an article about 'email marketing' is going to be much harder to rank on Page #1 of Google than an article about ‘email marketing funnels’.
But when a pillar page has a series of sub-topic pages linking to it, it has a much better chance of ranking on Page #1.
Because it’s at the center of a topic cluster and that means it has topical authority.
3. What is Topical Authority?
In 2013 Google introduced the Hummingbird algorithm and semantic analysis.
This algorithm allows Google to recognize that certain keywords cluster together in predictable patterns.
That in turn allows Google to map out the sub-topics that make up any topic.
And that means that Google is able to measure the topical authority of a piece of content.
In other words, Google is able to measure how well a piece of content covers a particular topic.
And that’s where topic clusters come in.
It’s difficult for a single piece of content to cover a topic definitively.
But what about a series of articles, each of which covers a different aspect of that topic?
That’s going to have topical authority.
And topical authority is now a ranking factor.
So the pillar post at the center of that topic cluster is going to rank well in Google.
4. Topic Clusters vs Keyword Optimization
Topic clusters are beginning to replace keywords.
Ten years ago, people used to focus on individual keywords.
But with Hummingbird and RankBrain the focus now is context, not isolated keywords.
Increasingly, Google is trying to understand searcher intent, and that means the algorithm is trying to understand context and meaning.
Gone is the era when you could optimize a page for a single keyword.
5. Topic Clusters and SEO
When you create an interlinked cluster of pages around a pillar page, you signal to Google that there’s a semantic connection between these linked pieces of content.
And that’s exactly the kind of content that search engines are now favoring: semantically-related content.
Also known as topic-based content.
Search engines are favoring sites that cover a particular topic with authority.
Because the search engines realize that visitors to a website that has topical authority are likely to find all the answers they need in one place, instead of having to visit multiple websites.
The website with well-organized topic clusters is going to rank better in the search results.
But there’s another reason why content clusters perform well in the search results.
Because the pages in a content cluster are interlinked, when one page gets an SEO boost it transfers link juice to the other pages in the topic cluster.
6. How to Create Content Clusters from Scratch
Here’s how to create a content cluster:
Take the head keyword for your main topic (e.g. ‘email marketing’, ‘seo’, ‘rock climbing’) and type it into Google.
Quickly scan through the first ten articles that appear in the search results.
Look at the headings and the sub-headings.
Make a list of the sub-topics that your main topic divides into.
When you’ve finished this exercise, type your head keyword into Google again.
This time look at the ‘Auto Suggest’ topics.
See if there are any additional items that you can add to your list of sub-topics:
Then scroll down to the foot of the page and look at the Google ‘Related Searches’.
Again, check to see if there are any additional sub-topics you can add to your list:
Now take your list of ‘email marketing’ sub-topics and write 200 to 300 words on each of the sub-topics.
You’ll end up with long-form article of 2,500 to 5,000 words.
Of course, 200 to 300 words is nowhere near enough words to cover any of the sub-topics.
That’s where your satellite pages come in.
Each satellite page will address one of those sub-topics.
And that’s your content cluster!
Watch this Video: 'Topic Clusters: The Next Evolution of Content Strategy' (1 min, 39 secs)
7. How to Create Content Clusters from Existing Content
To create content clusters from your existing articles and blog posts you first need to do a content audit.
Specifically, you need a spreadsheet of your articles so that you can examine the titles and see which of your articles would naturally fit into a topic cluster.
You can do this with a simple plugin called Export Post Info.
After installing and activating this plugin, enter a name for your download file, click ‘save Changes’, and then click on the download link:
The plugin creates a CSV file with the following columns:
- Number of words
Open the CSV file in Microsoft Excel and create a new column titled ‘Topic Clusters’.
In the new column you just created, make a note of the broad topic of the article. Then sort the spreadsheet by the column titled Topic Clusters.
You’ll find small groups of articles that share the same broad topic. These are your topic clusters:
In each topic cluster there may be an article that will serve as the pillar post for that topic cluster.
If not, you can easily create one using the process I outlined in the previous section.
When creating topic clusters from your existing content, remember to remove all the previous internal links that lead to other pages on your website.
You want the search engine bots to clearly recognize that this is a self-contained topic cluster.
And that means that the internal linking should be restricted to the cluster itself.
8. How to Create Internal Links Within a Topic Cluster
There are various ways of doing internal links in a topic cluster.
Here are some examples.
Topic Cluster Example #1 - The Anatomy of a SaaS Marketing Site
This topic cluster uses a Table of Contents at the top of each of the cluster pages:
At the foot of each page, it provides a link to the previous page and a link to the next page.
This is a great linking strategy:
- a Table of Contents navigation ensures that every cluster page links to every other page
- the top navigation gives the reader an overview of what the topic cluster consists of
- the bottom navigation encourages the reader to follow a sequence of pages
Topic Cluster Example #2 - Moz Guide to Content Marketing Strategy
This topic cluster uses the same two kinds of navigation as the previous example: ‘Table of Contents’ navigation as well as ‘Previous and Next’ navigation:
Topic Cluster Example #3 – Moz Beginners Guide to SEO
This topic cluster, also from Moz, uses these same two internal linking techniques:
From an SEO point of view the vital linking strategy in all three examples is the ‘Table of Contents’ linking:
- It tells the search engines that this is a topic cluster
- If one page in the topic cluster gets a ranking boost, the benefit will be passed on to the other pages in the cluster
The 'Related Articles' panel at the foot of this blog post is another example of internal linking within a content cluster.
9. Using ‘Related Article’ Blocks To Create Topic Clusters
A few weeks ago, I sat down and tried to work out how to create content clusters out of my existing content.
I knew that Google is now using clusters of semantically related content to decide how relevant your content is to a given search query.
And I wanted to make sure that my content was organized into these kinds of clusters.
So, I decided to place a ‘Related Article’ block at the foot of each of my blog posts. These blocks would contain links to 3 to 5 articles on semantically related topics.
But I needed a way to group my 70-odd published articles into semantically related clusters.
In short, I needed some software that would rank my online content into thematically related groups.
The kind of software I needed was the software used by ‘Related Posts’ plugins. But where could I find such software? And how much was it going to cost me?
I started Googling it.
And then it hit me...
I had the best topical relevance algorithm in the world, staring me in the face!
Google had already indexed all of my online content. So, I would get Google to tell me what my content clusters were.
Here’s how to do it:
Take any article that you have optimized for a particular keyword.
Then go to Google and type in inurl:yourdomain +keyword
The keyword is the main keyword you optimized your article for.
Google will list the blog posts on your website that share the most topical relevance for that keyword.
In the example below, I'm calling the article that contains the 'Related Articles Block' the host article.
Then create a box at the foot of your article and title it 'Related Articles'. Copy and paste the titles of your related articles. Insert links to those article and you have a topic cluster.
Organizing your content into topic clusters will help rank your articles higher in the search results. This is because search engines are now focussing on context and topical authority, rather than single keywords.
In this article I’ve shown you how to create new content clusters from scratch and also how to organize your existing content into content clusters.
A vital aspect of content clusters is internal linking.
Each page in the cluster should be linked to every other page in the cluster, preferably using a ‘Table of Contents’ linking strategy, as outlined above.
If you’re looking for a single SEO strategy that will lift your rankings in the search engines – this is the one!
This post was most recently updated on July 10th, 2020