Your complete guide to SEO, AEO and GEO
Search used to mean one thing: ten blue links, ranked. It now means at least three. Google still ranks pages, but it also generates answers above them, and a growing share of discovery happens inside engines that never show a results page at all: ChatGPT, Perplexity, Gemini, Claude. Each behaves differently, cites differently, and rewards different work.
This guide covers all three disciplines in one place, in plain language, with the primary sources linked so you can check every claim:
- SEO, search engine optimization: being found and ranked by search engines. Still the foundation everything else stands on.
- AEO, answer engine optimization: being the source an engine quotes when it answers the question directly instead of listing links.
- GEO, generative engine optimization: earning citations inside generated answers, where research shows quotations, statistics and cited sources are what move visibility.
Why one guide and not three
Because the disciplines share one pipeline. Google's own guidance on AI features in Search is explicit: its generative experiences are grounded in the same core ranking systems that power classic Search, and a page must be indexed, crawlable and snippet-eligible before any AI feature can use it. There is no separate index for AI answers. Work that ignores SEO does not get a seat at the AEO or GEO table.
At the same time, ranking and being cited are not the same achievement. A page can rank third and never be quoted; a page can sit on position eight and be the one sentence an engine lifts into its answer. The gap between those outcomes is what AEO and GEO are about, and it is why this guide treats them as their own chapters rather than a footnote to SEO.
The state of play, in numbers
- Research on generative engines finds that adding quotations lifts visibility by around 41 percent, statistics by around 30 percent, and cited sources by around 27 percent. Structure alone produces none of those gains.
- Across 7,683 pages and 47,097 citations, Gemini cited content updated within the year 78 percent of the time, ChatGPT 73 percent and Perplexity 65 percent, while only 42 percent of cited content had been recently published. Freshness is a citation signal.
- Across 1,000,000 pages and 100,000 results pages, top-10 positions contain 8.4 to 11.7 percent pages that are at least 80 percent AI generated, with stable impressions over twelve months. AI authorship in itself is not what Google acts on; the scaled, templated pattern is.
- Google states plainly that llms.txt files are ignored by Google Search, that no special markup or AI files are needed, and that no third-party tool has access to its internal ranking or AI systems.
How this guide is organised
Three chapters, from foundation to frontier. Start where your question is:
- SEO: what still matters, how Google ranks, whether AI content is penalized, and where the scaled content abuse policy draws the line.
- AEO: what answer engines are, how they choose their sources, and how AI Overviews, ChatGPT, Perplexity, Gemini and Claude differ.
- GEO: the research on getting cited, what Google actually recommends (and debunks), and how to measure visibility without fooling yourself.
Two pages sit across the chapters. SEO vs AEO vs GEO compares the disciplines and sorts out the naming. What content automation actually does describes the work a platform can honestly take off your hands, and what no platform can promise. The checklist and the glossary close the guide.
Who wrote this
Vupie builds content and link infrastructure for organic and AI search, so we work inside these systems daily. The guide stands on primary sources, not on our opinions: where a claim comes from Google's documentation or published research, it is linked. Where something is unknown or unknowable from the outside, we say so.