What is the difference between SEO, AIO, AEO and GEO — and which ones matter?

The four, in one sentence each

SEO — Search engine optimization

Search engine optimization (SEO) is the work of earning a position in Google’s organic results and local map pack for the searches a business wants — through technical health, content built around real search demand, a complete Google Business Profile, consistent citations and reviews.

AIO — AI optimization

AI optimization (AIO) is the work of making a business legible to AI systems — one consistent entity with the same name, services, area and facts on every page and profile, expressed in structured data and plain-text files a model can parse without guessing.

AEO — Answer engine optimization

Answer engine optimization (AEO) is the work of getting a page selected as the answer to a question — in Google AI Overviews, featured snippets, voice assistants and chat interfaces — by opening with a direct, self-contained answer, using question-shaped headings and marking FAQs up with FAQPage schema.

GEO — Generative engine optimization

Generative engine optimization (GEO) is the work of getting a business cited and recommended inside the answers generative engines write — ChatGPT, Gemini, Perplexity, Copilot and Google AI Mode — by publishing citation-worthy specifics, being corroborated by independent sources, and keeping the entity consistent and current.

The acronyms arrived within a couple of years of each other and the industry has not settled on them, so you will see AEO and GEO used interchangeably and AIO used to mean almost anything. The definitions above are the ones we work to, and they are the ones in the glossary and in the structured data on this site, so a machine reading this page gets the same four sentences you do.

How they depend on each other

The mistake is to treat them as four menus to pick from. They are four floors of one building.

• SEO is the ground floor. A fast site, pages for each service and city, a complete Google Business Profile, consistent listings, reviews. Every engine above reads these. A business with no SEO has nothing for AEO or GEO to work with.
• AIO is the plumbing. One entity, described identically everywhere, expressed in structured data and plain text a model can parse. It does not produce a call on its own; it is what lets a machine be sure who you are.
• AEO is the second floor. Pages that answer a question directly, under a heading shaped like the question, with FAQs marked up so they can be lifted whole. This is what puts you in a featured snippet, an AI Overview, a voice answer.
• GEO is the top floor. Being the business a generative engine names when someone asks for a recommendation. It is won by being retrievable, specific enough to quote, and corroborated by sources the engine already trusts.

Notice that nothing on the upper floors replaces the ground floor. The engines that write answers retrieve their sources from the same web Google indexes, and for a local question they lean hard on the Business Profile, the reviews and the directories. Skipping SEO to “do GEO” is building the roof first.

Which ones matter for a local business right now

Honestly: SEO still produces most of the calls, because most people with a leaking roof still type “roofer near me” and call someone from the map pack. That is where a local business should spend first and most.

AIO is next, not because it produces calls directly but because it is cheap and permanent. Consistency, schema, an llms.txt file and open crawl access are done once and maintained. They are also what lets every engine — Google included — trust the record. Most of the businesses we check fail this floor without knowing it: three versions of the name, two phone numbers, a category on the profile that does not match the site.

AEO and GEO are where the growth is, and where the competition is thin. For a growing share of questions the customer reads an answer and never sees a list of ten links; the business named in that answer gets the call. In the checks we run across five engines, the answers for a local trade vary by engine and by day, and it is common for no business to be named consistently. That is an open seat, and it is taken by the business with the clearest, most corroborated record, not the biggest.

So the order is: SEO, then AIO, then AEO and GEO as one program. Not four line items. One AI SEO program that stands on the SEO layer.

What each one looks like on a real service page

Take a water heater replacement page for a plumber.

• SEO: the page exists, loads in under a couple of seconds on a phone, is titled for the search, links to the city pages, and the Business Profile lists “water heater installation” as a service.
• AIO: the page carries Service schema naming the business, the service and the area; the business name and phone match the profile exactly; the page is in llms.txt; no crawler is blocked in robots.txt.
• AEO: the first paragraph under the H1 says, in one sentence, what a water heater replacement involves and how long it takes; the FAQ answers “how long does a water heater last” and “tank or tankless” in full sentences that stand alone.
• GEO: the page states the specifics — brands installed, permit handled, haul-away included, same-day when called before noon, the warranty term — and those facts are repeated on the profile and in reviews that mention them.

One page, four floors. That is what an answer-first service page is, and it is how every page on a site we build is written from the first draft.

How you measure each one

SEO is measured the old way: positions in Search Console, calls and forms from the site. AIO has no metric of its own beyond “is the record consistent,” which our scanner checks. AEO shows up as featured snippets and AI Overview citations in Search Console and in the AI-search channel on the traffic dashboard. GEO is measured by asking: the same questions, of the same engines, every month, with three things recorded — named or not, cited or not, and who was named instead. A rate, never a score, and never a promise.