"AI search" gets talked about as one thing, but the major platforms pull from different sources, use different retrieval methods, and cite differently. A business optimizing for one is not automatically optimized for all four. Here's how they actually differ.
ChatGPT
ChatGPT operates two distinct modes that matter for AEO. Its base model answers from training data, with a knowledge cutoff, and typically doesn't cite specific sources for those answers. When it invokes live search (increasingly the default for anything current or local), it pulls from the web through its own crawlers, OAI-SearchBot and ChatGPT-User, and does cite sources for that portion of an answer. In practice, ChatGPT's search-mode citations tend to favor a smaller number of sources it treats as higher-authority, rather than citing broadly across many pages for a single answer.
Perplexity
Perplexity is built around real-time retrieval as its core design, not an add-on mode. Nearly every answer is grounded in live web sources, cited inline as numbered footnotes the user can click through directly. Perplexity's crawler, PerplexityBot, tends to draw from a broader set of pages per answer than ChatGPT's search mode, and is comparatively more willing to cite a smaller or lesser-known site if its content directly and clearly answers the specific question asked. This makes Perplexity, in practice, one of the more approachable platforms for a business that's done real content work but doesn't yet have significant brand recognition.
Google AI Overviews
AI Overviews sit inside Google's existing search results and draw heavily on Google's own search index, meaning traditional SEO signals (indexation, crawlability, established ranking factors) influence AI Overview eligibility more directly than they do for ChatGPT or Perplexity. AI Overviews also draw on Google's Knowledge Graph, its structured database of entities, which is part of why strong schema markup and a well-optimized Google Business Profile carry particular weight for this specific platform.
Gemini
Google's conversational assistant draws on a similar underlying foundation to AI Overviews (Google's index and Knowledge Graph) but in a more conversational, multi-turn format. Facts that already feed AI Overviews well tend to also serve Gemini, though the citation behavior in the conversational interface differs from what appears in the search results page.
Side-by-Side Summary
| Platform | Primary Data Source | Citation Style | Most Influenced By |
|---|---|---|---|
| ChatGPT | Training data + live web via OAI-SearchBot | Selective, favors fewer higher-authority sources | Entity authority, established credibility |
| Perplexity | Live web via PerplexityBot | Broad, numbered inline citations | Direct, specific content matching the question |
| Google AI Overviews | Google's existing search index + Knowledge Graph | Embedded within search results | Traditional SEO signals, schema, Knowledge Graph presence |
| Gemini | Google's index + Knowledge Graph | Conversational, varies by context | Same foundation as AI Overviews |
What This Means for Strategy
The foundational work, clean entity data, strong schema, deep topical content, genuine third-party trust signals, benefits all four platforms, because all four are ultimately trying to answer the same underlying question: can this business be trusted enough to recommend. But the platform-specific behavior matters for where extra effort pays off fastest. A business with strong existing Google visibility already has a head start on AI Overviews and Gemini. A business with well-structured, specific, genuinely useful content, even without major brand recognition, has real room to earn citations on Perplexity in particular. Treating "AI search" as a single target risks missing this, and optimizing for the platform where a business already has the shortest path to a citation is often the fastest way to see AEO results start showing up.
Curious which platforms are already citing you, and which aren't? Get in touch and we'll check all four, side by side, so you know exactly where the gaps are.