AI search, compared
Short, opinionated explainers on the acronyms and files shaping AI search. Each comparison covers similarities, differences, when to use each, a real-world example, and a verdict.
AEO vs SEO
AEO (Answer Engine Optimization) optimizes for direct answers in AI overviews and assistants. SEO optimizes for ranked links in search engines. They overlap, but the goals, formats, and metrics differ.
Read comparisonGEO vs SEO
GEO (Generative Engine Optimization) targets being recommended inside generative AI outputs. SEO targets being clicked from search engine results. GEO measures share-of-voice inside AI; SEO measures rank and CTR.
Read comparisonGEO vs AEO
GEO and AEO overlap heavily but emphasize different parts of the AI search stack. GEO focuses on being recommended inside generative answers; AEO focuses on being the answer itself.
Read comparisonllms.txt vs robots.txt
robots.txt tells crawlers what they're allowed to fetch. llms.txt tells AI models what's worth reading and how to interpret it. They serve different audiences and live next to each other at your domain root.
Read comparisonThe AI search glossary
If you're new to AI search, the acronyms multiply fast. Here's the working vocabulary in one place.
Optimizing for ranked lists of links on Google, Bing, and other classic search engines.
Optimizing for single-answer surfaces — voice assistants, Google AI Overviews, and the spoken responses of chat assistants.
Optimizing to be retrieved, quoted, and cited by generative AI assistants like ChatGPT, Gemini, Claude, and Perplexity.
A Markdown file at your domain root that tells AI models which pages on your site matter most.
Plain-text rules that allow or block specific user-agents — including AI crawlers like GPTBot and ClaudeBot.
Google's preferred structured-data format. Powers rich results and gives AI engines verified facts about your pages.
The file at /.well-known/ai-plugin.json that exposes your API as a callable tool for AI agents.
Side-by-side beats long-form
Most explainers on AI search read like a textbook chapter. By the time you finish, you understand each concept but can't tell your CMO which one to fund first. The comparison format forces a decision: given these two options, which one should I lean into?Every page on this hub ends with a clear verdict — not a "depends on your goals" non-answer.
How to use this hub
Pick the comparison
Closest to the decision in front of you (e.g. GEO vs SEO if you're allocating budget).
Read the differences
Skim the table and the 'when to lean into each' section.
Check the verdict
If it matches your situation, that's your answer.
Validate with a scan
Use the recommended files and run OptimAIze to confirm.
The history that led to these acronyms
One word: SEO
Google dominated discovery, ten blue links dominated answers, one playbook dominated tactics.
Synthesis arrives
ChatGPT launches. Engines start synthesizing answers instead of linking. Old vocabulary breaks.
GEO, AEO, llms.txt
New words for new surfaces: chat assistants, single-answer voice, agent manifests, AI-aware crawlers.
Synthesis changes the rules
Being mentioned beats being clicked
If the synthesized answer names your brand and describes you accurately, you got the value of the impression even though no one clicked. Brand mention rate inside AI answers is becoming the real top-of-funnel KPI.
Specificity beats breadth
A page that answers one question exhaustively beats a page that answers ten superficially — the engine extracts a passage and quotes it. Short, definitive paragraphs near the top of the page win. Long meandering intros lose.
Common confusions we'll clear up
Same technical foundation, different optimization target. SEO optimizes for rank position; GEO optimizes for quote selection and citation attribution. Tactics overlap maybe 60%.
Closely related but not identical. AEO targets single-answer surfaces (voice, AI Overviews). GEO targets multi-source chat assistants.
robots.txt is an exclusion file (what bots can't read); llms.txt is an inclusion file (what bots should prioritize). You need both.
Blocking GPTBot doesn't affect Googlebot. But blocking Google-Extended removes you from Gemini and AI Overviews — which increasingly decide classic Google traffic.
Outdated. JSON-LD is the format every major AI engine uses to verify facts. OpenAI, Anthropic, and Google have confirmed it improves citation probability.
Updated quarterly
Engines change behavior every quarter. We update each comparison at least quarterly and immediately when a major engine ships a behavior change. A sensible cadence for your own strategy is the same: quarterly review, with an interrupt for major announcements.
See how your site scores on all of them
OptimAIze audits classic SEO and the new AI search layer in one pass. Free, no signup.
Run free scanFrequently asked questions
Why are there so many acronyms in AI search?
Because the field is moving faster than its vocabulary. SEO covers Google blue links, AEO (Answer Engine Optimization) covers single-answer surfaces like AI Overviews and voice, GEO (Generative Engine Optimization) covers chat assistants like ChatGPT and Perplexity, and a handful of files (llms.txt, robots.txt, ai-plugin.json) cover crawler permissions. The acronyms overlap on purpose — the underlying work is one program, not three.
Which one should I prioritize first?
SEO foundations first (clean HTML, schema, fast pages, real backlinks), then AEO (FAQ + Speakable schema, answer-first paragraphs), then GEO (llms.txt, AI-aware robots.txt, citation tracking). In practice you can ship them in the same sprint — they share most of the technical work and reinforce each other.
Are these comparisons opinionated or neutral?
Opinionated. We've audited thousands of sites and we'll tell you when one approach clearly beats another in a given context. Every comparison includes a 'when to lean into each' section so you can match the recommendation to your situation instead of taking a blanket position.
How often do you update these pages?
Quarterly at minimum, and immediately when a major engine changes behavior (e.g. a new AI crawler launches or an existing one changes its respect for robots.txt). The AI search stack is young — comparisons that were true in 2024 are sometimes wrong in 2026.