Topic Clusters

A topic cluster is a pillar page supported by a group of interlinked articles on subtopics. It is the classic way to build topical authority and the structural foundation of modern SEO.

The pillar-cluster model replaced the old “one keyword, one page” approach. In the AI era, clusters matter more than ever—models pull from clusters of trusted sources, not from isolated pages.

Anatomy of a topic cluster

• Pillar page. A comprehensive overview of the broad topic, usually 2,000–5,000 words
• Cluster pages. Each covers a single subtopic in depth, usually 800–1,500 words
• Internal links. Every cluster page links up to the pillar and sideways to siblings
• Anchor text. Descriptive, varied, and natural. Avoid exact-match anchors for every link

Why topic clusters work

• They signal topical authority to search engines and AI models
• They cover the whole question space, capturing long-tail and conversational queries
• They create many internal link paths, distributing page authority
• They make it easy to add new content over time

How to build a topic cluster

1. Pick the topic. Narrow enough to own, broad enough to be meaningful
2. Map the subtopics. List every question, entity, and sub-question in the topic space
3. Write the pillar first. It should be the best overview of the topic on the web
4. Write the cluster pages. One subtopic each, in depth, with internal links
5. Interlink densely. Every cluster page should link to the pillar and at least 2–3 siblings
6. Update quarterly. Add new data, new entities, new subtopics as the topic evolves