Authority Density
The “concentration of useful, trustworthy, semantically coherent information within your ecosystem” — coined by Carolyn Shelby (publishing-volume-hurts-seo) as the metric AI retrieval rewards in place of page count. The one-line thesis: “visibility is no longer a volume game; it is a clarity game.”
Why it inverts the old model
Classic SEO rewarded coverage (more pages → more ranking surface). AI systems retrieve chunks and weight embeddings, so what matters is whether a topic resolves to one dominant semantic center rather than being scattered across many near-duplicate pages. Volume that used to compound now causes semantic dilution and internal vector competition (pages competing for embeddings, not just rankings) — so density, not volume, is the lever. Raising it means consolidating fragments and structuring pages for extractability (clear headings, lists, declarative, focused paragraphs).
Relationship to brand depth
Authority density is the site-ecosystem / supply-side companion to the entity framing of brand-depth-ai-recommendations: brand depth = entity salience + coherence + relationship density across the web; authority density = the same coherence pressure applied within your own ecosystem. The shared root is E-E-A-T-style credibility re-expressed in embedding-space terms, and both feed GEO. They share the spoke’s standing caveat: the payoff is unmeasured — there is no metric for whether higher density actually improved AI consideration.
Related
publishing-volume-hurts-seo · brand-depth-ai-recommendations · keyword-cannibalization · generative-engine-optimization · e-e-a-t