OpenAI lets advertisers target ChatGPT users by uploaded email, phone number or Android ad ID
OpenAI lets advertisers target ChatGPT users by uploaded email, phone number or Android advertising ID, according to 404 Media's tests. Prompts that users may assume are private are a targeting input too.
The Watch · Security desk
Key figures: an uploaded list must be more than 25,000 entries long to target an audience, otherwise those users can only be excluded; ChatGPT has one billion monthly active users, as 404 Media reports; an OpenAI spokesperson says uploaded files are usually deleted within 24 hours of upload.
| Figure | Value | Note | Claim |
|---|---|---|---|
| Uploaded list length needed to target, more than | 25,000 entries | smaller lists can only exclude users | 10 |
| ChatGPT monthly active users | 1,000,000,000 users | as reported by 404 Media | 17 |
| Uploaded files usually deleted within | 24 hours | per an OpenAI spokesperson | 19 |
What happened
- OpenAI checks advertiser-uploaded lists against real ChatGPT users, and 404 Media says an advertiser can be a big business or essentially a random person.
- To target an audience, the uploaded list must exceed 25,000 entries. Smaller lists can only be used to exclude those users from an ad.
- An OpenAI spokesperson told 404 Media that uploaded files are deleted after processing, usually within 24 hours of upload.
- 404 Media ran two test ads that said ChatGPT isn't private and linked to its Project Lily article on contractors reading real users' prompts.
- OpenAI introduced ChatGPT ads in the U.S. in February, expanded to other territories, and this month added ads beside image generation results.
Why it matters
- exposure 404 Media has separately shown that humans may review users' prompts. The same text now also feeds an ad system.
- constraint The ads personalization opt-out stops use of past chats, activity and preferences. The setting itself says ads may still be based on the current chat, so a user has no switch that removes the live prompt.
- exposure Advertisers can upload raw emails and phone numbers. Meta hashes such uploads, and OpenAI did not say whether it does, so the handling of raw personal data sits with OpenAI.
ChatGPT's ad system has two separate targeting controls. The first is topical. An advertiser writes "context hints," and OpenAI's site says they "guide matching but aren't exact-match targeting rules." [6] 404 Media's hint asked for people searching for privacy topics, including "the privacy of ChatGPT chats themselves." [7] When a Free or Go user types a prompt, the chatbot will often show a related ad at the bottom of the answer. [4]
The second control is the list. Advertisers upload raw or hashed emails and phone numbers, or Android advertising IDs, and the ad follows the people who match. [9]
404 Media calls the ad targeting available in ChatGPT "somewhat standard practice across the advertising industry." [15] The novel part is the prompt, which is also an input. [2] 404 Media reports that ChatGPT has one billion monthly active users. [17]
Zach Edwards, co-founder of DecryptAds, a company that collects online advertising data for research, told 404 Media that OpenAI is doing what other large companies do when they start to monetize their audiences: "they are boiling the frog and hoping their users won't notice the privacy implications from their new ads." [14] [13]
The limits on advertisers come from OpenAI. A spokesperson told 404 Media that "advertisers cannot see which individuals matched or select specific people within an audience." [11] That is the company's statement. The campaign tools 404 Media used show the context hint field and the audience options, but the claim about matched individuals is not something the tests demonstrate.
What to watch
- Whether OpenAI answers if it hashes raw emails and phone numbers at upload, as Meta's system does.
- Whether OpenAI changes the personalization setting so it covers the current chat.
- Whether ads beside image generation results and in new territories bring new targeting inputs.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap+10
- Incentives45
- Confidence60
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
According to 404 Media's own tests of ChatGPT's advertising ecosystem, OpenAI lets anyone inject ads into ChatGPT users' sessions, targeting groups of people based on their email address, phone number, or a unique identifier on their phone.
- [2]
ChatGPT's ad targeting is novel in that it is also based on the prompts users enter into the chatbot, which users may assume are private.
- [3]
OpenAI first introduced ChatGPT ads in the U.S. in February, then expanded to other territories, and this month pushed ads alongside image generation results.
- [4]
When a Free or Go user types a prompt into ChatGPT, the chatbot will often display a related advertisement at the bottom of its answer.
- [5]
404 Media ran two advertisements inside ChatGPT reading 'ChatGPT isn't private. OpenAI hires humans to read users' chats. Learn more,' with a link to its article on Project Lily, in which contractors read real users' ChatGPT prompts.
- [6]
OpenAI's site says of advertiser context hints: 'Describe the conversations, topics, or keywords where your products or services may be relevant; these hints guide matching but aren't exact-match targeting rules.'
- [7]
404 Media added the context 'people searching for topics that discuss privacy, or the privacy of ChatGPT chats themselves, or people who are asking about current technology and AI topics.'
- [8]
An advertiser, which can be a big business or essentially a random person, can create an 'audience' of specific ChatGPT users to target; OpenAI checks whether uploaded raw emails and phone numbers correspond to a real ChatGPT user, and if so the advertiser can target those people.
- [9]
Besides raw emails and phone numbers, OpenAI's audience options include hashed emails and phone numbers and Android advertising IDs, which are unique identifiers issued to every Android phone.
- [10]
To make an audience ready for inclusion in targeting, the uploaded list must be more than 25,000 entries long; otherwise those users can only be marked for exclusion.
- [11]
An OpenAI spokesperson told 404 Media: 'Being on an advertiser's list does not, by itself, cause an ad to be shown. Inclusion filters and audience bid adjustments require at least 25,000 matched users, and advertisers cannot see which individuals matched or select specific people within an audience.'
- [12]
ChatGPT users can opt out of 'ads personalization,' but that does not stop ads or tracking entirely. The setting reads: 'Allow ChatGPT to use your past chats, activity, and preferences to select ads. Ads may still be based on your current chat.'
- [13]
Zach Edwards said OpenAI's advertising products are operating 'just like most other massive companies which start to monetize their audiences' and that 'they are boiling the frog and hoping their users won't notice the privacy implications from their new ads.'
- [14]
Zach Edwards is co-founder of DecryptAds, a company that collects online advertising data for research purposes.
- [15]
404 Media describes the ad targeting available in ChatGPT as 'somewhat standard practice across the advertising industry.'
- [16]
404 Media has previously shown that users' ChatGPT prompts may be reviewed by humans.
- [17]
404 Media reports that ChatGPT has one billion monthly active users.
- [18]
Meta's advertising system hashes the data when someone uploads raw emails and phone numbers. OpenAI did not answer when asked whether it does the same, and reiterated that advertisers can upload both raw personal data and hashed versions.
- [19]
An OpenAI spokesperson told 404 Media that uploaded files are deleted after processing, which is usually within 24 hours of upload.
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Sources
1 independent publisher whose own reporting we read for this story.
- 404media.coHow ChatGPT Targets Ads To You Based On Your Prompts, Phone Number, and Email
1 article · October 15, 2026
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