How AI answers pick their sources: training data, live retrieval and citations.

The best free resources

1. AI features and your website — — (Google), Google Search Central (current (no date shown))
   Primary source: query fan-out, link selection, AI Overviews vs AI Mode.

2. Retrieval-Augmented Generation (RAG) Explained: How AI Decides Which Pages to Search & Cite — Louise Linehan, Ahrefs (2026-07-09)
   Best plain explanation of retrieval vs training data and chunk selection.

3. How AI Mode Works and How SEO Can Prepare for the Future of Search — Mike King, iPullRank (2025-05-27)
   Technical teardown of AI Mode components, fan-out and passage-level selection.

4. How ChatGPT Does Query Fan-Out (15 Million Queries Studied) — Louise Linehan, Ahrefs (2026-10-12)
   Large data: only ~14% of ChatGPT answers search; how fan-out queries look.

5. How AI Is Changing Google Search and SEO (Search Off the Record ep. 109) — Martin Splitt, Nikola Todorovic (Google), Google Search Central podcast (2026-05-01)
   A Google Search engineering director on how AI features are built and tested.

6. ChatGPT search (Help Center) † — — (OpenAI), OpenAI (current)
   Primary source on when ChatGPT searches the web and how it shows sources.

7. How does Perplexity work? — — (Perplexity), Perplexity (current)
   Perplexity's own description of real-time retrieval and numbered citations.

Curated by effectiveGEOstrategy.com. Every link checked 2026-11-10. Know a better free resource? Tell us.