OpenAI lets anyone inject ads into ChatGPT users’ sessions, targeting specific groups of people based on their email address, phone number, or a unique identifier on their phone, according to 404 Media’s own tests of ChatGPT’s advertising ecosystem.

While the ad targeting available in ChatGPT is somewhat standard practice across the advertising industry, the chatbot’s one billion monthly active users may not understand they, in some cases, are being specifically targeted because of their personal data the advertiser has uploaded to OpenAI. ChatGPT’s ad targeting is also novel in that it is also based on the prompts users enter into the chatbot, prompts that users may assume are private but which, as 404 Media has previously shown, may be reviewed by humans. Or in this case, used for ad targeting purposes.