No. It absolutely does not scan the entire internet every time you ask a question. There are two different things happening, and mixing them up is where most confusion about AI search, and most bad AEO advice, comes from.
What the AI already knows, no search involved
The model was trained beforehand on a huge amount of text, and that knowledge is encoded directly into its parameters. Ask something like "why is the sky blue," and it usually does not search anything at all. It generates the answer from what it learned during training, the same way a person answers a question from memory rather than looking it up.
This split is bigger than most people assume. A Semrush analysis of 80 million real ChatGPT queries found that only about 46 percent actually trigger a live web search. The other 54 percent get answered entirely from training data, no retrieval, no citation, nothing to optimize toward. Whether a given question falls into the 46 percent or the 54 percent is not random. Queries with time sensitive markers, current prices, or highly specific local questions are what typically trigger the search path.
When the AI actually searches the web
For questions that need current information, the system sends a few targeted searches, not one giant query, to a search index. Ask "best plumber in Bozeman Montana" and it might issue something closer to three separate searches: best plumber Bozeman MT, emergency plumber Bozeman, plumbing companies Bozeman reviews. This is called query fan out, and different AI systems do it differently. Gemini and Google's AI Mode break a question into several sub queries run in parallel against Google's own index. ChatGPT rewrites the prompt into one or more targeted queries and sends them to Microsoft Bing, plus a few trusted partners for categories like weather and stocks. Perplexity runs its own index alongside third party providers. Claude fetches directly from the open web rather than going through a search partner.
The index was already built, long before your question
The search infrastructure behind all of this already has billions of pages indexed. The AI is not visiting billions of sites in real time when you hit enter, the expensive crawling and organizing work happened beforehand, the same way Google does not discover and read millions of pages after you press search. Your query searches the index that already exists. AI search adds a real layer on top of that same foundation: internet, crawled and indexed beforehand, search retrieval at question time, the AI reading a small set of selected results, then reasoning over them to generate an answer.
The AI does not read whole pages either
Even the pages that do get retrieved are not read in full the way a person would open a browser tab. Early in the process, the system often sees only metadata for each search result, the page title and meta description, before deciding whether that page is worth reading further. Once a page is selected, the model typically reads matching passages rather than the entire document. A retrieval might surface your page because one specific paragraph answers the query, even if the rest of the page covers something else entirely.
Why this matters directly for AEO
ChatGPT does not need to "know about" every business on the internet. The real question is whether the retrieval system surfaces a business as relevant evidence when a specific question gets asked. A genuinely good company with a strong website can still never make it into the small set of information a model actually sees for a given query, not because the business is unremarkable, but because retrieval never selected it. That is also exactly why a page broken into clear, self contained sections with specific claims retrieves more easily than the same information buried in one long, undifferentiated block, a passage has to be extractable to get pulled out and used.
Why two AI systems can give completely different answers
Ask the same question on two different AI systems and the recommendations can come back completely different. Their retrieval systems, indexes, ranking methods, query expansion patterns, and reasoning all differ. ChatGPT is searching Bing's index through its own query rewriting logic. Perplexity is searching its own index plus partner data through a separate ranking pipeline. Google's AI Overviews are grounded natively in Google's own index. None of these systems are reading the same set of pages for the same question, so there is no reason to expect them to land on the same answer.
The What Is Answer Engine Optimization guide covers what this actually means for getting a business surfaced, and the AEO, GEO, and AI SEO service at Omni Online Strategies builds the technical and content system that gives a retrieval system an actual reason to pick a page in the first place.