Observed Signal · Sep 23, 2026 · Policy Update · Source: https://martech.org/feed/ · Impact: 4/5 · Sentiment: Negative
Privacy Market: OpenAI Testing Third-Party Tracking in ChatGPT Ads
OpenAI is reportedly testing a third-party-style tracking mechanism in its ChatGPT advertising ecosystem. An independent researcher found that a cookie named '__obi' can be set by ChatGPT and persist for up to a year. When the user later visits websites that use OpenAI's advertising pixel, the same identifier is transmitted back to OpenAI along with page and conversion data. This enables cross-site attribution of ad interactions to subsequent user activity. The cookie is classified by OpenAI as an analytics cookie, which raises concerns about consent, as it may be set even when users decline marketing cookies. For marketers, this could improve conversion measurement in ChatGPT ads, but it also raises privacy and regulatory questions, especially given the sensitive personal data shared with ChatGPT.
This is a significant development from a major AI platform (OpenAI) entering advertising with potential third-party tracking, which could have wide implications for privacy, consent, and the future of AI-driven advertising.
Key Takeaways & Evidence Grounding
- OpenAI is testing a third-party-style cookie called '__obi' for ChatGPT ad tracking.
- The cookie can persist for up to a year and is sent to OpenAI when visiting sites with its ad pixel.
- The cookie may be set even when analytics consent is given but marketing cookies are declined.
- The research was published by a researcher known as Buchodi.
- The practice raises privacy concerns due to the personal data shared with ChatGPT.
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