What are Topic Clusters in Topic-Based Search Marketing?

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Topic-based SEO strategy is optimizing your website content around topic clusters. If you’re new to topic-based SEO you may be wondering what topic clusters are and how you can use them to build your site’s authority and optimize your website to drive traffic from organic search.

What are Topic Clusters?

A topic cluster is a method of structuring content on your website in an organized way to inform search engines that your site contains information related to a specific topic. The content is organized such that there is a core page (or pillar page) and a group of topic-related blog posts that all target keywords related to the main topic of that cluster. Adding internal links from the supporting blog pages to the core/pillar page creates an internal linking structure that informs search engines that your website is authoritative on that topic.

The topic-based content model is best explained visually. Here’s how a topic cluster should look.

content marketing pillar page and topic cluster example

What is a Topic Cluster Strategy in SEO?

One of the most important things in SEO is the authority of your site. While it’s easy for your content to be authoritative in one area, say digital marketing, it can be quite difficult to be authoritative across different topics like content marketing, PPC, and web design. One way around this is by using what are called “topic clusters.” Topic clusters are groups of closely related topics that help you be more relevant and appear as an authority on a given subject.

Pillar pages (also known as core pages) are at the center of topic clusters. (See Content Marketing in our example above.) The point of pillar pages is to associate your company with a certain topic, so if someone is searching for that keyword phrase, you will have an easier time being found in the SERPs. Since pillar pages cover a topic in-depth, they tend to earn topical authority and naturally earn backlinks. This helps your site grow its link profile with many links pointing back to the most important pages on your site.

Connected to each pillar page are cluster pages (typically blog posts) that cover the subtopics related to the pillar/core topic. This content hierarchy helps Google understand what your web pages are about, thus helping the search engine serve up your content for search queries your audience uses to find your business.

The Advantages of Using Topic Clusters

The main advantage of using topic clusters in your SEO strategy is that, over time, you will build a web of authoritative content on your site that sends signals to the search engines that your content should be shown near the top of the search results because it best answers searchers’ queries.

Another benefit of topic-based SEO is that it can help you diversify your keyword portfolio if you are targeting highly competitive keywords. The wider the breadth of content that is associated with a specific topic, the more likely it is to rank for less competitive long-tail keyword terms.

The benefit of topic-based search marketing for your target audience is that topic clusters make it easier for people to find your content in search results. The process naturally produces content that is authoritative and covers a topic comprehensively. Your site becomes a one-stop-shop for all things related to a topic. This keeps potential customers on your site longer as they consume more of your content, begin to trust you, and continue on their path to conversion.

Lastly, this method of SEO gives your website a natural structure that is better understood by search engines and your audience. By creating content clusters instead of standalone articles, each blog on your site will have a purpose that ties it together with other related cluster pages on your site.

How do I Implement a Topic Cluster Strategy?

1. Keyword Research to Create Topic Clusters

The first step with any SEO campaign is keyword research. Concentrate on topics that relate to the main topic of your website and branch out into related terms, phrases, or long-tail versions of these keywords. It’s also important that you don’t go overboard and try to cover every single term under the sun. You want to limit yourself to a more manageable number of topics so that you don’t dilute your focus and confuse your visitors.

To begin the topic keyword research process, define what your company wants to be known for (or rank for) and all the characteristics that make up that topic or concept. What are all the products, solutions, or services that your company provides? Those will be your core topics or pillar topics. Here’s an illustration of SMA Marketing’s Topic Focus.

Topic Clusters Infographic

It will be very difficult to rank for these broad, high-level topics. However, by focusing on more targeted terms that are commonly searched by our audience, we have an opportunity to rank for related terms that will drive relevant organic traffic to our site. Using the topic “SEO” as an example, keyword research helped us narrow down the search queries related to SEO that we have an opportunity to rank for, such as:

  • SEO agency
  • SEO strategy
  • what does SEO mean
  • what is SEO and how does it work
  • search engine ranking
  • Google search engine optimization

Each of these subtopics is a related term or question that relates to the core topic. Covering these subtopics will inform Google that we have authority and expertise on the core topics.

To determine these subtopics, begin by answering the following questions. This will help you stay focused during your keyword research.

  • What questions is their target audience asking around the core terms?
  • What pain points/problems does your product, solution, or service solve?
  • What are the related or common terms that are used to describe your core topic?
  • What are similar concepts that are connected?

To gather this information, we recommend using:

  • Google Search Engine Results Page
  • SEMrush Topic Research and Keyword Magic tools

Research the Google SERP

Head over to Google and type in your core topic. Review the top search results and you will see the related terms that Google considers to be connected to your core topic. For example, if our core topic is Content Marketing, we can see that the top-ranking terms and the terms that Google thinks are relevant, are terms related to the definition of content marketing and what is content marketing.

content marketing topic cluster terms

Looking at the People Also Ask rich feature, we can also see the common search queries related to content marketing, including; examples of content marketing, the basics of content marketing, the role of content marketing, and what is good content marketing. On the right side of the SERP, we see the knowledge panel for content marketing, which lists the importance of content marketing, content marketing goals, how to start content marketing, and content marketing metrics. If you scroll down the SERP to the Related Searches, you’ll see additional subtopics, including content marketing strategy and types of content marketing.

content marketing related searches

On the SERP alone, we’ve uncovered 12 potential subtopics to use in our Content Marketing cluster!

Using SEMrush to Perform Topic Cluster Research

SEMrush has a few content marketing and SEO tools we can use to uncover keywords for our topic clusters. Our favorites are the Topic Research Tool in the Content Marketing Toolkit and the Keyword Magic Tool in the SEO Toolkit.

SEMrush Topic Research Tool

Navigate to the Topic Research tool in the Content Marketing Dashboard. Enter your core topic. Then click Mind Map. You’ll get a great visual of the related topics.

semrush topic research mind map

You will also get a list of headlines and questions that you can use to create your subtopics.

semrush topic research headlines
semrush topic research questions

At this point in your research, you will have many subtopics you can choose from – possibly too many. Now, it’s time to narrow down the list. We need to understand the search volume and keyword difficulty of the potential terms. SEMrush’s Keyword Magic Tool and Keyword Manager will help you compile the data you need to make an informed decision about the subtopics to focus on.

SEMrush Keyword Magic Tool and Keyword Manager

Navigate to the Keyword Magic Tool in the SEO Dashboard. Enter the core term or a term you are researching. You’ll notice many of the terms that came up in the previous two steps are included in this list. To create a list that you can download as supporting data for your topic cluster, select the terms you want to include in your cluster, then click “Add to Keyword Manager” and create a master list of terms for your topic cluster. Once you’re finished adding terms from the Keyword Magic Tool to the Keyword Manager, navigate to the list in Keyword Manager and export the list.

SEMrush keyword magic tool example

A good way to narrow down your list of topics based on the data is to look at the search volume. Is there enough volume to make it worth your time publishing content on this topic? Also, look at the Keyword Difficulty, which will tell you what your chances are of ranking in the top 10 – the higher the score, the less likely you are to snag a coveted spot on the first page of the SERPs. Also, look at the Intent of the search query – Informational, Commercial, Navigational, or Transactional. Does it match the content that you would publish on this topic? If so, that may be a good topic to cover. And finally, take a look at the keyword trend. This will shift over time, but you may want to deprioritize any keyword that is trending down.

2. Map Out Your SEO Topic Clusters

Now, it’s time to create a system to map out your topic clusters and track the data. Create an Excel or Google Sheet, with columns for the following:

  • URL
  • Page Type (core or cluster)
  • Target Term
  • Monthly Search Volume
  • Average Rank [Current Date] (This is your average rank over the past 3 months for the target term. Get this from Search Console.)
  • Average Rank [Future Date] (Track how the average rank improves over time.)

You should have one core page and multiple cluster pages for each topic cluster. Create a separate tab on the sheet for each topic cluster you build. The result of this work is that you now have a content plan that you can work from to optimize and create new content for your site.

3. Write Pillar Content for Your First Cluster

Pillar pages aim to increase your visibility in the SERPs for a given keyword phrase while also linking back to more important internal pages on your site. With your research to guide you, create your first topic cluster by choosing a primary topic that you want your business to be seen as the authority on and publish a pillar page that covers the topic comprehensively.

A pillar page can be a resource page, online guide, or long-form blog post. The format isn’t as important as is the comprehensiveness of the content. This article or page will cover a broad topic and touch on some of the subtopics that you researched in step one. Pillar pages tend to be long-form content that covers the topic comprehensively. Aim to publish a piece of content that is at least 2,000 words long that answers several questions your audience may have about that particular topic.

When you map out your topic clusters (Step 2 above), you will want to determine whether or not you already have existing content on your site that covers the cluster topics you determined during your keyword research. If a page already exists for a particular topic, you should optimize it for the cluster topic keyword and add relevant content to the blog to improve it. (We like to use Frase for this purpose.)

Where there are content gaps, you will want to publish new articles for the relevant topics in that cluster.

Your topic cluster map may look something like this:

seo cluster example

Internal linking is how you connect one page to another on your site. This has the obvious benefit of helping people find other important pages within your site, but it also helps search engines crawl and index all of the internal pages on your site, which is crucial if you want them to rank for any particular keyword phrase.

Each pillar page will include internal links to the supporting blog articles and the articles will include internal links back to the pillar page, thus creating an internal linking structure within your content. You should also link related articles to each other. You can include links to those related posts in the sidebar of your website or within the body of the article, using anchor text that is specific to the page you are linking to.

Next, create another article for each subtopic keyword that you want to target. The length of your supporting blog articles should be at least 350 words. More important than the length of the article is that the content covers the topic deeply.

Each blog article should follow these blog SEO best practices, such as:

  • Keyword in title tag
  • Keyword in H1 heading
  • Keyword in first paragraph
  • Link to core page in first paragraph
  • At least 1 external link to an authoritative page
  • Internal link to another blog article in the cluster
  • Keyword and related keywords in a subheading
  • Keyword and related terms throughout the body of the article where they make sense contextually
  • Keyword in the meta description

6. Repeat the Process for Other Topic Clusters

You’re just getting started building your site’s topical authority, so don’t stop now! Follow the same process for other topics you want your website to rank for.

Optimizing Content for Topic Cluster SEO

What’s the sense in working so hard to create content around topic clusters if you aren’t going to also follow other SEO best practices?

Optimizing content for topic cluster SEO begins with high-quality content that satisfies the intent of the searcher. It should cover a topic comprehensively and follow on-page SEO best practices by including the main keyword in the title, heading(s), meta description, and linking to other related pages in the cluster as mentioned in the list above.

Optimizing pages for topic cluster SEO also includes adding structured data and content that will help it earn the featured snippet and other SERP features, such as People Also Ask and FAQ. If a video is included on the page, Video schema should be added to the page to help it earn a spot in the Video SERP feature. Not only that, it should be optimized for semantic SEO so that Google better understands how it relates to other content on your site through entities and your knowledge graph. Content optimized for topic clusters should also be error-free and optimized for technical SEO.

All of these aspects of SEO are essential to giving your content the best chance of ranking in the top search results.

Does a Topic-Based SEO Strategy Work?

Topic cluster SEO is a relatively new content strategy and you will need to determine whether or not it works for you. It takes consistent content publication, diligently following SEO best practices, and setting up tracking to measure your results.

Use an SEO tool like SEMrush to set up position tracking for your core topics and subtopics and track their ranking over time. Our data suggest that this strategy is most effective with keywords that follow these two criteria:

  • The subject matter is well-known to your target audience and has enough search volume to support the effort to create the pillar and blog content.
  • The topic itself includes related topics that provide multiple opportunities for articles and link building.

A topic-based SEO strategy works best when the pillar page is the only page on your website about that specific topic and each blog article covers a different topic related to the pillar content. This avoids keyword cannibalization and reduces the chances of your web pages competing against each other in search results.

Ideally, you would have both high-quality internal linking AND consistent, on-topic pillar and blog content that support the keywords you are trying to rank for.

If you follow these steps correctly, then you will have a content plan that your SEO strategist and content team can work from to build out your topic clusters. Soon, you’ll be on your way to creating SEO authority for your website around the topics that will drive qualified visitors from organic search.

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