Common Crawl
Common Crawl is a nonprofit that publishes a free, massive archive of crawled web pages, which has served as a foundational training dataset for many large language models.
Common Crawl is the open web archive much of AI was trained on. It's a nonprofit that regularly crawls the public web (via CCBot) and releases the data for free, and that corpus has been a core ingredient in training many large language models.
Its significance for AEO is mostly conceptual: being in Common Crawl historically meant being part of the raw material models learned from. But it's a training dataset, not a live retrieval index, so presence in it doesn't make an engine cite you today — that's the job of search crawlers and crawlable content. Understanding the difference keeps "are we in the training data" separate from "are we getting cited," which are distinct questions.
Example. Many well-known models list Common Crawl among their training sources. A page included in those crawls may have shaped what a model "knows" generally, without that page being the source a grounded answer links to now.
Relevant pillar
Related terms
- CCBotCCBot is the crawler operated by Common Crawl, whose open dataset is a foundational training source for many AI models, so allowing or blocking it shapes how widely your content trains AI.
- Training DataTraining data is the body of text and other content an AI model learns from during training, shaping what it knows by default before any live retrieval is involved.
- Large Language Model (LLM)A large language model is an AI system trained on vast amounts of text to predict and generate language, and is the engine that writes the answers in AI search.