A researcher going by the handle Buchodi has published a technical report alleging that OpenAI has built an ad tracking system into ChatGPT. According to Buchodi, ChatGPT generates a unique ID, links it to a user account, and stores it in a cookie called __obi for the .openai.com domain. This ID is then used to match user behavior on third-party sites back to their ChatGPT account.

'bazaar' Codename and a Tracking Pixel for Third-Party Sites

Buchodi describes the chatbot's ad platform under the codename 'bazaar' and breaks down the entire tracking flow. In his report, the ad code meant for integration on outside websites works just like a tracking pixel.

How the Tracking Works, According to the Report

The report says that when you launch ChatGPT, it creates a unique identifier tied to your account and saves it in the __obi cookie. This identifier then gets used in the bazaar platform's tracking chain to connect your actions across the web with your ChatGPT account when you visit other sites.