Chapter 05 — The Privacy Model

The privacy model is the contract that makes ChatGPT Ads possible without breaking the trust that makes ChatGPT useful. Read it carefully — it shapes everything an advertiser can and cannot do.

What advertisers never receive

• Chat content.
• Chat history.
• Memories.
• Personal details about the user.
• Any individually identifiable user data.

There is no API endpoint, no dashboard view, no support escalation that surfaces this data to advertisers. The wall is structural.

What advertisers do receive

• Aggregated, non-identifying performance data — total views, total clicks, etc. The Insights endpoints (Chapter 19) are the canonical surface.
• Direct messages from users who choose to message the advertiser through the ad. The advertiser only sees what the user explicitly sends them — not the surrounding chat.
• Pixel and Conversions-API-attributed downstream events — page views, add-to-cart, orders. Tied to the privacy-preserving oppref identifier rather than user identity. Chapters 8, 9, and 11.

How conversation data flows

Conversation data is used inside ChatGPT to make ads relevant. It is not shared with advertisers. This is the whole shape of the contract:

[user's chat] -> [OpenAI ranking] -> [eligible ad selected] -> [shown to user]
                                              |
                                              +--> [advertiser sees: aggregate stats only]

The advertiser never sees the chat. The user never sees the advertiser’s account. OpenAI sits in the middle and brokers relevance.

What this means for measurement

oppref is the bridge. The pixel captures it from the landing-page URL on click and stores it in a first-party cookie. The Conversions API forwards it on every server-side event. None of this exposes the user’s chat to the advertiser — oppref is intentionally privacy-preserving — but it lets the advertiser tie a downstream conversion back to a click that originated in ChatGPT.

The measurement chapters (8, 9, 11) document the mechanics. The privacy contract above is what makes those mechanics legible: an advertiser can prove a conversion came from ChatGPT Ads without ever seeing the user behind it.