The idea of creating topic clusters for SEO with pillar pages and supporting pages has been around for a while. Hubspot covered the topic very well in their article. Basically, the idea is to have one page that covers the topic very well, but also have other related supporting pages that cover some aspects of the topic. This way you create more topical authority than if you only had one page.
There are ways as to how you can interlink those pages. In our example we will use “SEO audit” as the pillar page and Title Tag Audit, Images Audit, URL Audit, Internal Links, Headings and Page Speed Audits as supporting pages.
Some common ways of creating topical clusters are:
- Pillar page links to just one of the supporting pages. All supporting pages link to the pillar page. All supporting pages link to just one other supporting page.
- Pillar page links to all of the supporting pages. All supporting pages link to the pillar page. All supporting pages link to just one other supporting page.
Keyword Cannibalization
In either of those cases there cannibaliazation. Google may mix up which page is more important for a subtopic, pillar page or a supporting page. One way to avoid this is to link from the pillar page to the supporting pages using anchors that do not contain the main keyword, but are still descriptive. For example, our pillar page will link to “Page speed audit” page using something like “you can improve page loading” instead of “Page speed audit” as anchor text. This way “Page speed audit” page will actually not compete with the pillar page for words that include “audit”.
“Page speed audit” page will also not mention the main word “audit” more than necessary. In my experience it is enough to mention it in the title tag and URL just once, and couple of times in text. This will keep the pages relevancy in our topic cluster, but will not compete with the pillar page for keywords that include “audit”. Pillar page should have a whole section on “Page speed audit”, usually with a H2 heading and related subheadings, to keep its relevancy for the topic.
Over-optimization
When linking to the pillar page from all the other supporting pages, there is risk of overoptimizing the pillar page if interlinking is not done properly. Especially if the pillar page is heavily optimized for that keyword. If you are using SEO tools that automatically link to other pages, some of them will always use the same anchor text (in our case that would be “SEO AUDIT”).
The safest way to link from supporting pages to the pillar page is to use anchor text that seems more natural. The best way is to include stop words to make it look more descriptive and natural. Page about some aspect of “page speed audit”, instead of linking to the pillar page with “SEO AUDIT” as the anchor text, should link with “we can improve page speed after an audit” instead. Or something like that…you get the idea. This will also signal relevancy because we are linking from a page about some aspect of “page speed” to a page that describes page speed in more detail.
Another important thing to keep in mind when it comes to over-optimization of the pillar page is not to mention the all words from the main keyword in the headings more than necessary. Google will be able to figure out that the subsection of the page is about “TITLE TAG AUDIT” even if you don’t mention “audit” in the H2 heading of that section.
Some SEO studies (SEOalgoSecrets and my own test), show that stuffing H2 with keywords leads to over-optimization. To be safe, only include the main keyword in H2 headings if the words in H2 are not obviously semantically related to the main keyword.