If you’ve optimized for one AI search engine, you have not optimized for all of them. That’s the core lesson buried in the second module of Ahrefs’ AEO course — and it’s the mistake most brands make when they treat “AI search” as a single monolithic target instead of a handful of very different systems with very different rules for who gets cited.
Google AI Overviews, ChatGPT, and Perplexity all produce the same basic output — a synthesized answer with sources — but they get there through different pipelines, pull from different corners of the web, and reward different kinds of content. Here’s how they actually diverge.
Google AI Overviews: An Extension of the Search Index You Already Know
AI Overviews aren’t a separate ranking system bolted onto Google — they’re a summarization layer sitting directly on top of Google’s existing index and ranking signals. That’s why AI Overviews show meaningful overlap with traditional organic results: much of what gets pulled into the summary is coming from pages that were already ranking well in classic search.
The practical implication is reassuring and slightly boring: the SEO fundamentals you already know — solid on-page structure, authoritative backlinks, technical crawlability, satisfying search intent — still carry weight here. AI Overviews reward the same kind of content that ranks well organically, just packaged into a synthesized answer instead of a list of links.
ChatGPT: Consensus Over Novelty
ChatGPT operates differently because it isn’t purely retrieval-driven the way Perplexity is, and it isn’t a direct extension of one search index the way AI Overviews are. It blends its training-time knowledge with live browsing, and when it does browse, it shows a preference for sources it can trust broadly — reference sites, encyclopedic sources, and, notably, comparison and “best of” content, including pages built by competitors comparing you to them.
This is a subtle but important shift in strategy. If ChatGPT is more likely to cite a third-party roundup that mentions your brand than your own product page, then getting listed favorably in comparison content, review roundups, and industry “best tools” articles becomes as important as optimizing your own site. Being talked about accurately elsewhere on the web starts to matter as much as what you say about yourself.
Perplexity: Real-Time, Citation-First, and Community-Driven
Perplexity is the most transparent of the three about its sourcing — it shows its citations directly and updates near-instantly, since it’s built around real-time retrieval rather than a periodically-updated index or a blended training corpus. That transparency also makes it the easiest platform to measure yourself against: you can literally see which citation position you hold for a given query.
Perplexity also leans unusually hard on community and forum content — Reddit threads show up as sources at a strikingly high rate. That’s a meaningful signal: authentic, well-regarded conversation happening about your brand or product in public forums may do more for your Perplexity visibility than a polished landing page ever will.
Why the Differences Matter
Put side by side, the three platforms reward three different things:
| Platform | Primary signal | What it rewards |
|---|---|---|
| Google AI Overviews | Existing search ranking signals | Strong technical and on-page SEO |
| ChatGPT | Consensus and trusted references | Being mentioned in comparisons, roundups, and encyclopedic sources |
| Perplexity | Real-time retrieval and community discussion | Fresh content and authentic forum/community presence |
None of these strategies conflict with each other — but none of them alone covers all three platforms either. A brand that only chases traditional SEO will do fine in AI Overviews and stall out in Perplexity. A brand that only chases community buzz might do well on Perplexity while staying invisible to ChatGPT’s more conservative, consensus-driven citation habits.
The Takeaway
“Ranking” in AI search isn’t a single position to chase — it’s closer to a portfolio of trust signals spread across a search index, a language model’s training and browsing habits, and a real-time retrieval system that treats forums as legitimate sources. Optimizing for AI search means building presence across all three simultaneously: solid SEO fundamentals for AI Overviews, credible third-party mentions for ChatGPT, and active, authentic community discussion for Perplexity.
The engines look similar from the outside. The paths to getting cited in each one are not.