GEO vs SEO vs AEO: what they mean, and what Google says about them
SEO earns you a ranked link a person clicks. AEO earns you the direct answer a search engine displays. GEO earns you a mention inside a generative assistant like ChatGPT. They are three different surfaces with three different mechanics, and winning one does not win the others: in a test of 15,000 long-tail queries, only 12% of the URLs AI assistants cited ranked in Google's top 10 for the same prompt.
SEO: earning the ranked link
Search engine optimisation is the original discipline: make a page the best answer for a query so it ranks, and a person clicks through to your site. It still works and it still pays, because a click is a visitor you can measure and convert.
AEO: earning the direct answer
Answer engine optimisation targets the answer shown above or instead of the link list. Google's version is AI Overviews and AI Mode, which retrieve relevant pages from its index, generate an answer, and link to the pages that support it.
Ahrefs looked at 863,000 keyword result pages and 4 million AI Overview URLs as of March 2026 and found that 37.9% of URLs cited in AI Overviews also appeared in the first ten blocks of the same page of results. So classic ranking helps here, but it accounts for well under half of what gets cited.
GEO: earning the mention
Generative engine optimisation targets assistants that compose an answer from many sources at once. There is often no result page at all, and frequently no click.
This is the surface where a Google ranking carries across least, and it is where that 12% figure comes from. Per engine the spread was wide: Perplexity 28.6%, Gemini 8.6%, Copilot 8.2% and ChatGPT 8% for in-text citations, so "AI search" is not one channel behaving one way.
What Google says about these terms
Google's guide to its generative AI features, updated in July 2026, is direct about this. From Google Search's perspective, optimizing for AI Overviews and AI Mode is optimizing for the search experience, so it is still SEO. Those features are rooted in Google's core ranking and quality systems.
The same guide lists things you can ignore for Google Search:
- llms.txt and other AI-specific files or markup.
- Breaking content into small chunks for AI.
- Rewriting pages just for AI systems.
- Chasing inauthentic mentions.
What it does ask for is original, people-first content on a sound technical foundation. Assistants outside Google, such as ChatGPT and Perplexity, behave differently, which is why they are worth measuring separately.
Why all three, and in what order
- SEO still drives the clicks you can attribute and convert today, so it stays the foundation.
- For Google, AEO is the same work: AI Overviews and AI Mode draw on its core ranking systems, mostly at the informational stage.
- GEO covers the assistants outside Google, where your existing rankings transfer the least.
The honest sequencing is that they share most of the same underlying work. A genuinely useful page, organized with clear headings and checkable facts, serves all three, and for Google you do not need to write it any differently. The differences are in measurement, not in three separate content programmes.
The measurement trap
Because these surfaces overlap so little, one blended "visibility score" across them is misleading by construction. Measure each surface on its own, with its own prompt set and its own sample size, and keep the numbers apart.