At a glance: ChatGPT and Perplexity agree on almost nothing. Across 100,000 identical prompts, only 11% of cited domains appeared in both engines. ChatGPT leans on authoritative reference and editorial sources; Perplexity leans heavily on Reddit and community content. One generic "AI optimisation" strategy cannot win both — you need a per-engine AEO plan, measured per engine.
What this covers
- The headline number: 11% overlap, two separate ecosystems
- ChatGPT vs Perplexity vs Google AI Overviews: citation behaviour compared
- Why the engines diverge: three mechanical reasons
- 1. Different retrieval pipelines, different shortlists
- 2. Different freshness appetites
- 3. Different definitions of trust
This is a technical summary. The full guide — with the data, tables and worked examples — is on our site: *ChatGPT vs Perplexity: Why They Cite Completely Different Sources (2026 Per-Engine AEO Guide)*.
LeadsNow AI builds pay-per-result AI lead generation and answer-engine-optimisation systems in Australia.
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