Every topical map has two main sections: the core and the outer. The core section contains the essential topics and entities that directly define your site’s expertise. The outer section contains related, supportive, and contextual topics that extend coverage and demonstrate depth.
This distinction isn’t about hierarchy or value judgment. Both are necessary. The core gives you authority, while the outer provides breadth.
Why They Matter
Search engines look for two signals when evaluating a site’s topical map:
- Authority → Does this site cover the central subject thoroughly?
- Completeness → Has this site explored related areas that provide context and depth?
- The core section answers the first question. It tells Google, “This site is built on these foundational topics.”
- The outer section answers the second. It shows Google, “This site has expanded to cover related aspects, proving expertise and thoroughness.”
A site with only core content may appear shallow. A site with only outer content may appear unfocused. A strong topical map needs both sections, connected and structured.
Core Section Explained
The core section includes the pillars of your topical map. These are the non-negotiable topics that directly support your central entity. Without them, you cannot claim authority in your niche.
Example 1: Cybersecurity Blog
- Core topics: network security, malware prevention, encryption, identity protection.
- These topics are inseparable from cybersecurity itself. They define the subject and directly reinforce the central entity.
Example 2: Fitness Coaching Website
- Core topics: strength training, nutrition fundamentals, cardio programming, recovery techniques.
- These are the building blocks of personal fitness. They form the foundation for expertise.
Mistakes to Avoid in Core Sections:
- Diluting focus by chasing trendy but irrelevant content.
- Creating core topics but failing to interlink them into a coherent structure.
- Overlapping content (multiple pages on the same core subject without distinction).
Outer Section Explained
The outer section adds depth, context, and supporting detail. These topics don’t define your niche on their own but are critical for completeness. They help connect the dots, answer long-tail queries, and expand semantic relevance.
Example 1: Cybersecurity Blog
- Outer topics: famous security breaches, ethical hacking, compliance regulations, security tool reviews.
- While not pillars, they provide real-world application, breadth, and depth around the core.
Example 2: Fitness Coaching Website
- Outer topics: workout gear reviews, fitness apps, hydration strategies, mindset and motivation tips.
- These topics reinforce the core without replacing it, showing search engines that the site covers fitness holistically.
Mistakes to Avoid in Outer Sections:
- Overloading with loosely related lifestyle content (e.g., a fitness site writing about unrelated celebrity diets).
- Leaving outer content disconnected from the core (no linking back to foundational topics).
- Treating outer content as filler instead of strategically chosen extensions of the core.
How Core and Outer Work Together
Think of a topical map like a geographic map:
- The core section is made up of the major cities and highways. These define the structure of the map and make it navigable. They are the essential points that orient everything else.
- The outer section includes the smaller towns, scenic routes, and landmarks. They don’t define the map on their own, but they add richness, detail, and context that make the map complete.
Without the core, the map lacks structure. Without the outer, the map feels bare and incomplete. A strong topical map includes both, connected together, so search engines (and readers) can see the full landscape of your expertise.
Structuring Authority and Depth
The core section establishes authority. The outer section builds supporting context and depth. A strong topical map requires both, with clear boundaries and strong interlinking.
By distinguishing between core and outer content, you not only structure your site more effectively but also send stronger signals to Google about what you do and how completely you cover it.
👉 This note continues the series after Source Context and Central Entity. Next, we’ll look at how to use these principles to actually build and scale topical maps for your site.
