Nearly half of internet users now consult AI chatbots when researching products or services, creating an advertising surface that is both growing and largely invisible. Research published Monday by Adblock Plus found 72% of US adults are concerned their private conversations with AI assistants will be used to target them with ads.
The scale of the shift is notable: 49% of internet users have used AI to find information in the past month, equivalent to roughly 1.59 billion people globally, and 23% say AI is now their primary source when researching brands, products or services ahead of conventional search.
Tests of ChatGPT and Copilot conducted in August 2026 for the report document two different approaches. ChatGPT places an advertiser's creative in a labeled box positioned after the answer. Copilot generates its own ad copy in the assistant's voice, tailored to the user's prompt, with a sponsored disclosure appearing after. In both cases, the ad matches the prompt context but need not relate to the answer the assistant has given.
Consumers who are aware of these arrangements are largely hostile to them. Those who expressed concern about AI ad targeting described the ads as annoying, intrusive, and trust-eroding, the research found. Adblock Plus said it has blocked more than 25 million ads on ChatGPT since 30 April, with 2.7 million blocked in the most recent week alone.
The more disruptive formats may still be ahead. Academics interviewed for the report note that advertising inside conversational AI works differently from traditional web display: rather than choosing between pre-designed creative assets, a chatbot ad system needs only a product keyword and a matching prompt, and can generate relevant ad copy on the fly. Dr. Florian Schaub, of the University of Michigan School of Information, explained: "In AI chatbots, targeting still works in similar ways, but those assets are no longer needed. The system only needs a keyword and product matching prompt."
The economics driving adoption are substantial. An estimated $7.6 trillion is required to scale the compute, data centres and energy infrastructure underpinning AI development at current projections, making advertising an increasingly significant revenue stream for the major players offering free-tier access.
Cornelius Witt, director of global public affairs at Adblock Plus, said: "We want to open this black box and our report is a first look inside the new AI ad economy and what it means for users."
Adblock Plus and its sibling product AdBlock have a commercial interest in making this case; their core product is ad blocking. The research nonetheless draws on consumer survey data and independent academic input, and the documentation of ChatGPT and Copilot ad mechanics is verifiable against the live products. The report is available on the Adblock Plus website.
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