Former OpenAI researcher Zoë Hitzig resigned on Monday, the same day the company began testing advertisements inside ChatGPT. In a New York Times guest essay, Hitzig warned that OpenAI's advertising strategy risks repeating Facebook's mistakes from a decade ago. She spent two years at OpenAI helping shape AI model development and pricing.

Hitzig argued that ChatGPT's accumulated personal data makes advertising especially risky, as users have shared medical fears, relationship problems, and religious beliefs with the chatbot. She described this as "an archive of human candor that has no precedent." The researcher drew parallels to Facebook's history, noting how the company's privacy promises eroded over time despite initial pledges to give users control over their data.

OpenAI announced in January it would begin testing ads in the US for free and $8-per-month "Go" subscription tiers, while paid Plus, Pro, Business, Enterprise, and Education subscribers would not see ads. The company claims ads will be clearly labeled and will not influence ChatGPT's responses. Hitzig's resignation comes amid a broader debate in the AI industry, with rival Anthropic declaring Claude will remain ad-free while running Super Bowl ads mocking AI advertising. OpenAI CEO Sam Altman defended the ad-supported model as a way to make AI accessible to users who cannot afford subscriptions.