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The Question That Started

It All

Metehan Yesilyurt, an international SEO consultant, had been working with Common Crawl datasets for seven months when he started asking a question that many in the industry have been avoiding: "What about the training data?"

As Metehan put it in his recent research: "Are there reasons why certain domains get recommended so frequently? How can we even find the answer to this?"

The answer, it turns out, lies within the monthly Web Graph releases—a resource that has been powering AI training for years, yet remains largely untapped by brand managers and marketing professionals. As we shift from traditional Search Engine Optimization (SEO) to Generative Engine Optimization (GEO), understanding the topology of the web is no longer optional. It is the new foundation of online presence.

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Common Crawl Web Graph: A Map of the Open Web

Every month, Common Crawl publishes Web Graph Data alongside its main crawl archives. This dataset isn't just a list of URLs; it is a mathematical representation of the entire internet's structure. Within this graph, two key authority metrics are computed across billions of links:

1. PageRank: The classic measure of authority based on the quality and quantity of links. It identifies which sites are "voted" for by other high-authority sites. 2. Harmonic Centrality (HC): A more nuanced metric that measures how "close" a domain is to all other domains. A domain with strong HC can reach the rest of the web through fewer "link hops."

While PageRank tells you who is popular, Harmonic Centrality tells you who is essential. It identifies the central hubs that keep the web’s information flow moving. For AI models, these hubs are the primary targets for data extraction.

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Harmonic Centrality: The New North Star for AI Visibility

In the world of LLMs (Large Language Models), being "crawled" is the prerequisite for being "known." The Mozilla Foundation’s 2024 report, “Training Data for the Price of a Sandwich,” confirmed that 64% of the 47 LLMs analyzed used filtered versions of Common Crawl data. For GPT-3, over 80% of training tokens originated here.

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• High HC Score: Your site is viewed as a "central hub."
• Crawl Priority: CCBot visits your site more frequently to ensure its data is fresh.
• Training Representation: Because you appear more frequently in monthly archives, your content is overrepresented in the datasets used to train the next generation of AI.
• AI Citation: When a user asks ChatGPT or Perplexity a question, the model draws on the most consistent, authoritative data it was trained on—your content.

This isn't just about "authority"; it’s about proximity to the core of the web.

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Quantifying the Connection: SEO vs. AI Ranking

Brie Moreau of White Light Digital Marketing recently processed over 2 million citations to see how these metrics translate to real-world AI visibility. The findings are a wake-up call for traditional marketers:

• The Google Correlation: There is a direct link between Google rankings and AI citations. A site in position #1 on Google has a 46-48% probability of being cited by an AI, while position #10 drops to just 19%.
• Content Type Matters: Comparative listicles dominate AI citations, making up 32.5% of all references. LLMs prefer structured, comparative data over simple commercial store pages (which represent only 4.73% of citations).
• The Co-Citation Effect: AI models use Reciprocal Rank Fusion (RRF) to blend results. If your site is frequently linked alongside other industry leaders (high HC neighbors), your chances of being cited increase exponentially.

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How SEOs

Are Using Web Graph Data Today

Forward-thinking marketing teams are moving away from chasing "blue links" and toward managing their "web topology." Here is how they are applying these insights:

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1. Strategic Link Building

(Topology Over Volume) Traditional link building focuses on getting any high-authority link. AI-focused strategy focuses on getting links from sites that are deeply embedded in the web's core. A single link from a high-HC site like Wikipedia or a major industry hub is worth more for AI visibility than dozens of isolated backlinks from niche blogs.

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Practical Applications for Brand Managers

To improve your Harmonic Centrality and, by extension, your AI visibility, consider these three pillars:

• Become a Resource Hub: Create data-rich, structured content (like the listicles mentioned in Moreau’s research) that other sites naturally want to reference as a primary source.
• Optimize for Interconnectivity: Ensure your site is easy for bots to navigate. High internal linking and clear site maps help CCBot understand your site's internal "centrality."
• Monitor Your HC Over Time: Track your rank history. If your HC is dropping, it means the web is growing around you, and you are becoming more isolated from the core.

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The Bigger Picture: From SEO to GEO

We are witnessing a fundamental shift in how information is discovered. The old model was "index and rank." The new model is "train and retrieve."

In this new paradigm, Harmonic Centrality is the metric that bridges the gap. It isn't just a technical data point; it is a measure of how integrated your brand is into the fabric of the internet. As AI becomes the primary interface through which customers find information, being "central" is the only way to remain visible.

As Stephen Burns, Web Intelligence Lead at Common Crawl, notes: "The topology of your backlink profile may matter as much as the volume. A single link from a site deeply embedded in the web's core could do more for your Harmonic Centrality than dozens of links from isolated sites."

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Take Control of Your AI Visibility

Is your brand a central hub or a digital island? The data to answer that question is already public. By leveraging Harmonic Centrality, you can move beyond the guesswork of traditional SEO and start optimizing for the AI-driven future.

Ready to bridge the gap between your content and AI training data?