A recent survey from Elon University’s Imagining the Digital Future Center found that half of Americans now utilize AI chatbots like ChatGPT, Gemini, Copilot and Claude. A study from the Stanford Institute for Human-Centered AI analyzed the privacy policies of six top US AI chat system developers—OpenAI’s ChatGPT, Google’s Gemini, Anthropic’s Claude, Amazon’s Nova, Meta’s MetaAI, and Microsoft’s Copilot—and found that all of them appear to use customer conversations to “train and improve their models by default” and “some retain this data indefinitely.” Cybersecurity expert George Kamide noted that many LLMs are trained or fine-tuned using user inputs, meaning conversations can contribute to the model’s future behavior. Experts advise against sharing personally identifiable information (PII), such as full name, home address, phone number, and government ID numbers, with chatbots, as this data could be logged or processed in ways that expose users to identity theft, phishing, or data brokerage activities.