ChatGPT Ads Can Target Users by Email, Phone Number and Android ID, 404 Media Finds
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404 Media ran its own ads inside ChatGPT and reported that advertisers can target users with uploaded email addresses, phone numbers or Android advertising IDs, as well as by conversation topics. OpenAI says uploaded files are usually deleted within 24 hours.
OpenAI lets advertisers target ChatGPT users with ads based on email addresses, phone numbers or Android advertising IDs they upload, according to 404 Media's tests of ChatGPT's advertising system, published October 15, 2026. 404 Media reported that the targeting can also draw on the prompts users type into the chatbot.
How the audience targeting works
404 Media reported that OpenAI lets an advertiser, "which can be a big business or essentially a random person," create what the company calls an "audience," a list of specific ChatGPT users to target. According to the report, OpenAI offers several ways to build one: uploading raw email addresses and phone numbers, uploading hashed versions of them, or uploading Android advertising IDs. OpenAI then checks whether the data corresponds to a real ChatGPT user, and if so the advertiser can target that person.
The report says an uploaded list must be more than 25,000 entries long to be used for "inclusion" targeting; otherwise the users can only be marked for "exclusion." 404 Media wrote that other ad systems, such as Meta's, hash the data when an advertiser uploads raw emails and phone numbers. It said OpenAI did not answer when asked whether it does the same, and instead reiterated that advertisers can upload both raw and hashed data.
An OpenAI spokesperson told 404 Media that uploaded files are deleted after processing, which is usually within 24 hours of upload. The spokesperson added: "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."
Prompts and "context hints"
404 Media ran two ads of its own inside ChatGPT to see how the system works. Both read, "ChatGPT isn't private. OpenAI hires humans to read users' chats. Learn more," and linked to the outlet's earlier article on Project Lily, in which, according to 404 Media, contractors read real users' ChatGPT prompts. The report says advertisers can also supply "context hints." OpenAI's site describes them as ways to "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." 404 Media entered a context hint aimed at "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."
The report notes that OpenAI first introduced ChatGPT ads in the US in February and has expanded them since. When a Free or Go user types a prompt, ChatGPT will often display a related ad at the bottom of its answer, and in October OpenAI began placing ads alongside image generation results, according to 404 Media.
Opt-outs and critics
Users can opt out of "ads personalization," but 404 Media reported that this 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."
Zach Edwards, co-founder of DecryptAds, a company that collects online advertising data for research, told 404 Media that "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." Edwards added: "We need to strengthen data broker laws so that advertisers sharing sensitive PII [personally identifiable information] with ad tech companies like OpenAI are required to register as data brokers and give people a clear process for removing their data from these systems."
404 Media itself noted that the ad targeting available in ChatGPT is "somewhat standard practice across the advertising industry," but wrote that the chatbot's one billion monthly active users may not understand that they can be targeted because of personal data an advertiser has uploaded.
The report also describes ChatGPT Ad Library, a site that says it probes ChatGPT with consumer prompts and records the ads that come back. The site says it has captured at least 43,410 ads across 415,289 placements, and states that its figures reflect its own sample and not OpenAI's internal data.