In recent research, the Washington Post worked with researchers at the Allen Institute for AI on the investigation to look inside the training data of popular chatbots. They categorized the websites using data from SimilarWeb, a web analytics company. They analyzed Google’s C4 data set, a massive snapshot of the contents of 15 million websites used to instruct some high-profile LLMs, including Google’s T5 and Facebook’s LLaMA. OpenAI does not disclose what datasets it uses to train the models backing ChatGPT.