For years, the conversation about cookies has been framed as a dispute between user privacy and advertising efficiency. A new study published in PNAS and picked up by Boston University compels us to rethink that narrative with concrete numbers: when third-party cookies disappear, the economic impact is not only absorbed by advertising platforms but also by publishers, content creators, independent media, and brands that rely on accurate measurement to justify their investment.
The research analyzed 200 million advertising impressions globally and found that when third-party cookies are removed, publishers' ad revenues fall by around 35%. In the European Union, where privacy regulation is considerably stricter, the decline approaches 66%. Alternative solutions like Google’s Privacy Sandbox recover only a limited portion of the lost value, according to the researchers.
The current scenario: neither cookies nor a final date
Google confirmed in 2025 that Chrome would maintain its third-party cookie opt-in scheme instead of eliminating them permanently, while continuing to explore privacy-protecting technologies in private browsing. The British competition authority documented the shift: Google moved from eliminating cookies in Chrome to allowing users to decide whether to keep them. This change of position has practical consequences for the industry: brands can no longer plan around a universal deadline for cookies and must operate in a fragmented ecosystem where Safari, Firefox, Chrome, mobile apps, CTV, retail media, and walled gardens have different rules from each other.
The result is less interoperability, pressured CPMs, weaker attribution, and greater reliance on closed platforms that concentrate the most valuable data.
The Mexican context
In Mexico, the new Federal Law on the Protection of Personal Data Held by Private Parties centers on the legitimate, controlled, and informed processing of personal data and informational self-determination. This means that it is not enough to capture consent: clarity, purpose, and proportionality in the use of data must be demonstrated. For marketing and AdTech teams operating in the local market, this raises the technical and legal standards for any audience data-driven strategy.
The risk of thinking that rejecting cookies automatically equates to a better digital experience is real. In practice, it may push towards less transparent models: fingerprinting, login walls, concentrated data on closed platforms, or forced subscriptions. For medium-sized publishers and specialized media, the central challenge will be to convert audiences into identifiable communities without compromising user trust.
According to the analysis by next+, cookies are not dying; they are losing dominance. And in this process, organizations that do not build their own architecture of first-party data, clear consent, and independent measurement of third-party tracking will increasingly be exposed to relying on more expensive intermediaries, harder-to-activate audiences, and measurement that does not accurately reflect the real impact of their advertising investment. For brands and agencies operating in Mexico, that is the problem that needs to be solved now, not when regulation or the market forces it.