ChatGPT now knows what you do on other websites via ad collector
OpenAI links ChatGPT accounts to third-party browsing data using a persistent cross-site cookie. Advertiser scripts transmit this identifier to OpenAI servers, enabling behavioral profiling across external sites. The author reproduced the mechanism using two independent capture methods and analyzed traffic from over one thousand hostnames. This confirms a new tracking pathway for developers building privacy-focused applications.
OpenAI establishes a persistent link between ChatGPT accounts and external browsing activity through a specific tracking cookie. This identifier allows advertiser scripts to transmit user behavior data to OpenAI servers. The author verified this mechanism using two independent capture methods. Traffic analysis revealed significant data collection across numerous external sites. Users who visit websites that deploy OpenAI advertising code are subject to this tracking pathway. The mechanism applies regardless of whether a user is logged into their ChatGPT account. Anonymous subject identifiers remain stable on a device for at least 27 days. The observed traffic included requests from various commercial websites. Consumers should review their consent settings carefully regarding analytics and marketing distinctions. The author noted that syncing occurred even when marketing consent was refused. Individuals may wish to avoid sites using specific OpenAI ad pixels. Further details about configuration options were requested from OpenAI on September 14.