{"version":1,"type":"story","url":"https://digestai.news/story/openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o","json":"https://digestai.news/story/openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o.json","markdown":"https://digestai.news/story/openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o.md","slug":"openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o","headline":"OpenAI's ad collector links off‑site browsing to ChatGPT accounts via obi cookie","summary":"OpenAI runs an ad‑tracking service at bzr.openai.com that creates a 22‑character identifier called **obi**. When a user is signed into ChatGPT, the client generates a JWT containing the identifier and the account ID, then stores the same value in a year‑long cookie scoped to *.openai.com*. Advertisers who buy ChatGPT ads embed a small OpenAI script on their pages; the script automatically sends the obi cookie back to OpenAI along with scraped data such as email, phone, name, and location.\n\nThe author reproduced the flow on an Android phone, captured traffic, and decoded 932 sync tokens. Of those, 736 were tied to logged‑in accounts and 196 to anonymous devices that persisted for at least 27 days. Observations covered 936 distinct advertiser pixels across 1,029 hostnames, with 685 scraped‑identity events versus 255 advertiser‑supplied ones. Postal codes appeared in 100 events across 28 sites, and URLs were stripped to origin plus path before transmission. The mechanism works on Chrome for Android but is blocked by Safari’s Intelligent Tracking Prevention and Chrome on iOS.\n\nOpenAI classifies the obi cookie as an analytics cookie in its policy, yet it enables cross‑site user profiling. The company’s support reply acknowledged the inquiry but gave no clarification.","keyPoints":["OpenAI's bzr.openai.com sets a year‑long “obi” cookie tied to a ChatGPT account and sends it to advertiser sites.","Study logged 936 advertiser pixels on 1,029 hostnames, with 685 scraped identity events versus 255 advertiser‑provided.","The cookie operates on Chrome for Android but is blocked by Safari ITP and Chrome iOS."],"whyItMatters":"Linking off‑site browsing to a ChatGPT identity creates a new privacy risk, giving advertisers insight into users’ behavior beyond traditional web tracking.","category":{"slug":"policy","name":"Policy & Regulation","url":"https://digestai.news/category/policy"},"entities":{"companies":["OpenAI","Meta","Chewy","Wayfair","HelloFresh","Coursera"],"models":[],"people":[]},"firstPublishedAt":"2026-09-20T15:18:44Z","updatedAt":"2026-09-20T15:18:44Z","sourceCount":1,"hasPrimarySource":false,"sources":[{"outlet":"buchodi.com","title":"ChatGPT now knows what you do on other websites via ad collector","url":"https://buchodi.com/chatgpt-now-knows-what-you-do-on-other-websites-via-ad-collector","publishedAt":"2026-09-20T15:18:44Z","type":"press","primary":false,"lead":true}],"sourceNotes":null,"discussions":[{"site":"Hacker News","url":"https://news.ycombinator.com/item?id=49776729","points":60}],"thread":null,"cite":{"text":"Digest AI, \"OpenAI's ad collector links off‑site browsing to ChatGPT accounts via obi cookie\", 20 September 2026, https://digestai.news/story/openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o","publisher":"Digest AI","title":"OpenAI's ad collector links off‑site browsing to ChatGPT accounts via obi cookie","datePublished":"2026-09-20T15:18:44Z","url":"https://digestai.news/story/openai-s-ad-collector-links-offsite-browsing-to-chatgpt-accounts-via-o"},"generatedBy":"Written by Digest AI's editorial model from the linked sources; the sources are the record.","license":"Headlines, digests and key points are written by Digest AI and may be quoted with a link to the story page. Linked articles belong to their publishers. Terms: https://digestai.news/terms#reuse"}