What is Topic Cluster?
A topic cluster is a content model where one long-form "pillar" page targets a broad head term, surrounded by multiple "spoke" pages targeting related long-tail sub-topics, all interlinked. It signals topical authority to Google's NLP models and dominates a category more effectively than isolated blog posts.
Worked pillar + spoke structure
| Page | Role | Target term | Links to |
|---|---|---|---|
| Rank Tracking (pillar) | Pillar | "rank tracking" | All 5 spokes below |
| SERP Volatility | Spoke | "serp volatility" | Pillar |
| Algorithm Updates | Spoke | "google algorithm updates" | Pillar |
| AI Overview Tracking | Spoke | "track ai overview rankings" | Pillar |
| Cannibalisation Detection | Spoke | "keyword cannibalization" | Pillar |
| Share of Voice | Spoke | "share of voice seo" | Pillar |
How Topic Cluster works
- Pillar page: 2,000-4,000 word comprehensive guide targeting the head term (e.g. "SEO reporting").
- Spoke pages: 800-1,500 word focused posts each targeting one long-tail variant (e.g. "SEO reporting for agencies", "monthly SEO report template").
- Every spoke links up to the pillar; the pillar links down to every spoke — creates a hub-and-spoke topology in Google's crawler map.
- Ideal cluster size: 1 pillar + 5-15 spokes. Below 5 = too shallow to signal authority; above 15 = keyword cannibalisation risk.
- Refresh the pillar every 6 months and add new spokes as long-tail opportunities emerge in GSC.
Example
A rank tracking pillar page interlinks with 10 spoke articles: SERP volatility, algorithm updates, AI Overview tracking, cannibalisation detection, share of voice, keyword grouping, position #0, competitor tracking, mobile rank tracking, and daily vs weekly cadence. Google reads the pattern as "this site is an authority on rank tracking".
Frequently asked questions about Topic Cluster
How is a topic cluster different from a regular blog?
A regular blog publishes disconnected posts. A topic cluster is a deliberate hub-and-spoke information architecture where every page is topically and structurally linked to a central pillar.
Do topic clusters help with AI Overview citations?
Yes — LLMs prefer citing pages that are part of coherent topical clusters, because the surrounding context signals expertise and trustworthiness.
What is the difference between a pillar page and a hub page?
Pillar pages are content-rich (2K+ words of actual explanation). Hub pages are mostly navigation (short intro + link list). Pillars rank; hubs distribute authority.
Related terms
Internal Linking
Internal linking is the practice of linking from one page on your site to another. It distributes ranking authority across your domain, helps crawlers discover new content, defines topical relationships, and signals to Google which pages are most important — all of it fully under your control.
Topical Authority
Topical authority is Google's assessment that your site is a comprehensive, trustworthy source on a specific subject. It's built by covering a topic deeply (breadth × depth × freshness) rather than chasing unrelated high-volume keywords. Sites with strong topical authority rank new pages faster and higher in their niche.
Long-Tail Keywords
Long-tail keywords are specific, multi-word search queries — usually 4+ words — with lower individual search volume but sharper intent and less competition. Collectively they drive 70%+ of all Google searches and convert at 2-5x the rate of head terms.