The main and inconvenient finding: schema markup does not affect citations in AI at all — statistical noise. Yet it is sold as the main 'GEO fix'.
More numbers:
— YouTube mentions — #1 factor for brand visibility in AI (correlation 0.737). Stronger than backlinks and DR
— 28.3% of the most cited ChatGPT pages are not visible in Google at all
— Listicles 'Best X' — 43.8% of all ChatGPT citations
Conclusion: AI search is not an overlay on SEO, but a parallel channel with its own rules. We mark up schema for classic snippets, but as 'optimization for
ChatGPT' — not sellable.
Source: Ahrefs
