What is SEO?
Search engine optimization (SEO) is the practice of making a page eligible and competitive in ranked results on Google and Bing. The unit of work is the page. The signals are crawlability, indexability, relevance to a query, internal links, page speed hygiene, backlinks, and demonstrated expertise. Success is measured in rankings, impressions, and clicks.
What is AEO?
Answer engine optimization (AEO) is the practice of making a passage on a page extractable as a direct answer. Surfaces include featured snippets, People Also Ask, voice assistants, and the answer capsules in Google AI Overviews. The unit of work is a 40 to 80 word passage under a question-shaped heading. Signals are answer-first structure, FAQ or HowTo schema, and visible entity names.
What is GEO?
Generative engine optimization (GEO) is the practice of making a page a source that generative engines will retrieve, ground on, and cite. Surfaces include ChatGPT Search, Perplexity, Gemini, Claude, Copilot, and Google AI Mode. The unit of work is a self-contained, specific passage. Signals are concrete statistics, named quotations, outbound citations, consistent entity names, author and date, freshness, and crawler access for search bots.
How do SEO, AEO, and GEO compare?
The three disciplines share one page and one crawler fetch, but they reward different structures. The table below summarizes the differences as XEO Agent uses them.
| Dimension | SEO | AEO | GEO |
|---|---|---|---|
| Goal | Rank in classic results | Be extracted as the answer | Be cited inside a generated answer |
| Primary surfaces | Google, Bing ten blue links | Featured snippets, People Also Ask, voice, AI Overview capsules | ChatGPT Search, Perplexity, Gemini, Claude, Copilot, AI Mode |
| Unit of optimization | Page | Passage under a heading | Passage plus its provenance |
| Winning format | Indexable page with clear title, headings, links | Question heading followed by a 40 to 80 word answer, then a list or table | Specific claims with sources, dates, and named entities |
| Key signals | Title, description, canonical, robots, H1, internal links, content depth | Question-led headings, short answers, FAQ or HowTo schema, entity names | Statistics, quotations, outbound citations, author, date, @id in schema, crawler access |
| Success metric | Rankings, clicks | Snippet or answer-box ownership | Citation share across engines |
| What XEO Agent checks | Technical, on-page, and content depth scores | Schema, answer patterns, entity coverage | Extractability, entity clarity, source quality |
What does Google say, and what do ChatGPT and Perplexity do?
Google's guidance for AI features states that no extra markup is required beyond being indexed and snippet-eligible. That is necessary but not sufficient for other engines, which retrieve differently. ChatGPT Search leans toward established publishers and specialist how-to pages. Perplexity favors fresh pages and community sources. Claude tends to ground on long, canonical documents. A page that only optimizes for Google's ranking still needs specificity and provenance to be cited elsewhere.
Published research supports this. The GEO paper by Aggarwal and colleagues (KDD 2024) found that adding quotations, statistics, and citations raised visibility in generative answers by roughly 30 to 40 percent, while fluency-only rewrites did little and keyword stuffing hurt. Those numbers are from a benchmark, not from XEO Agent, and results on any single site will differ.
What can a page-level audit tell you, and what can it not?
A page-level audit reads the HTML a server sends and reports what is present, missing, or malformed. It can tell you whether a page has a title, canonical, valid JSON-LD, question-led headings, a stated author and date, external references, and enough text to be worth citing. It can also flag pages whose content only exists after JavaScript runs.
A page-level audit cannot tell you whether an engine actually cited you, how often, or what it said. It does not measure backlinks, Core Web Vitals field data, or your competitors' share of answers. Use a page audit to confirm a page is citeable, then use search console data or an AI visibility tracker to see whether it was cited.
Where should you start?
Start with the on-page readiness checklist, which lists the exact signals XEO Agent scores, grouped by SEO, AEO, and GEO. Then read how scoring works for the fetch model and limitations. If you are choosing between a local auditor and a cloud tracker, the comparison of cloud AEO tools explains which job each one does.