Large language model (LLM)

A large language model is an AI system trained on vast amounts of text to predict and generate language, powering tools like ChatGPT, Claude, and Gemini. For brands it matters because these models now answer questions people used to ask a search engine.

A large language model (LLM) is an AI system trained on enormous amounts of text to predict what words come next, which turns out to be enough to answer questions, summarise, write, and hold a conversation. ChatGPT, Claude, and Gemini are the best-known consumer faces of this technology.

For a brand, the important shift is where these models sit: between a customer and their question. People increasingly ask an LLM the things they used to type into a search box — “who’s a good studio for X,” “is this company legit,” “what does Y cost” — and act on the answer without visiting ten links. That makes how a model describes you a real marketing surface, not a novelty.

Being represented accurately in that surface is the work of GEO and AEO. The broader shift is in search is splitting into three.

Quick recall

What is a large language model? An AI trained on huge amounts of text to generate language — the tech behind ChatGPT, Claude, and Gemini.

Why should a brand care? People now ask LLMs questions they used to search, and act on the answer without clicking through.

How do you influence what it says? Through GEO and AEO — helping the model describe you accurately.