Publishers cry foul over W3C crusade to rid web of third-party cookies

Exclusive Movement for an Open Web (MOW), an advocacy group that supports web publishers, has filed a complaint with the UK's Competition and Markets Authority (CMA) challenging the World Wide Web Consortium's (W3C) call to eliminate third-party cookies.

The term "cookies" refers to HTTP cookies, data sent by a server to a web user's browser. These key-value pairs serve various functions, such as session management, personalization, analytics, and tracking. They can be set by first-party sites – the site being visited – or by third-party sites if the publisher's web application code provides the necessary support.

Third-party cookies (3PCs) have long posed a privacy problem because they allow organizations with no relationship to web users to track their online browsing activities, often without legitimately obtained consent. While cookie-based tracking of this sort may not involve personally identifiable information (PII), it can be combined with other data sets to identify and profile people.

MOW, instrumental in derailing Google's Privacy Sandbox proposal, argues that the W3C's position opposing 3PCs is anti-competitive and supports Google to the detriment of web publishers. The organization maintains that smaller players would be at a disadvantage without 3PC data because they don't have access to large sources of first-party data like Apple, Google, and Meta.

3PCs have been blocked by default since 2019 in Mozilla Firefox and in Brave. The following year Apple Safari did the same, with Vivaldi following in 2021. Google Chrome announced plans to do so but has only enabled default blocking for users of Incognito mode. Microsoft Edge blocks some 3PCs by default.

In July 2024, the W3C, a global public interest non-profit focused on developing web standards, declared: "Third-party cookies have got to go," and earlier this month reiterated that position in a finding by the W3C Technical Architecture Group (TAG).

"Third-party cookies (cookies set by someone other than the website being used) have introduced additional vectors for cookies to be used as a data collection mechanism across websites," the TAG document claims. "This increase in data collection and sharing about people using the web – often in a way that is opaque or incomprehensible to a web user – results in decreased individual and collective privacy."

MOW co-founder Timothy Cowen contends that the W3C has been captured by Google – an objection dating back many years – and that the standards body's advocacy for cookie removal harms competition in the web advertising industry. The W3C has also been criticized for opacity in the past.

"The W3C, announcing that '3PCs must be removed,' sides with Google and against publishers," Cowen said in an emailed statement. "This is disappointing for what should be a neutral standards body."

The W3C didn't immediately respond to a request for comment.

The MOW complaint, provided to The Register, asks the CMA to contact the W3C seeking the withdrawal of the 3PC removal announcement. MOW's letter says the advocacy group wrote to the W3C on June 25, 2025, arguing the announcement violates antitrust obligations, but has not yet received a response. It also cites a January 2023 letter MOW sent to the CMA alleging that Google and Apple have been coordinating proposals that violate competition laws through standards bodies.

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The complaint further contends that the W3C's endorsement of 3PC removal should be seen as a violation of Google's commitments to the CMA – promises made to the watchdog to involve rivals in the design process of the now abandoned Privacy Sandbox.

A Google spokesperson said the company couldn't comment prior to seeing the complaint letter.

The W3C has been contemplating how the web might work without 3PCs since at least April 2023.

The Register understands that at the time that document was written, TAG included 11 people, one of whom worked for Google. TAG's rules specify: "Each organization represented in the group must have at most one vote, even when the organization is represented by several participants in the group (including Invited Experts)."

MOW's Cowen published comments on the initial draft in May 2023. He contends that 3PCs are not inherently intrusive and that unwelcome tracking arises from bad actors abusing the system.

In a phone conversation with The Register, Cowen said he hopes the CMA will consider the MOW filing in light of the UK's Digital Markets, Competition & Consumers Act 2024 (DMCCA), which gives the watchdog more market oversight powers.

And next week, Cowen expects Judge Amit Mehta to issue a ruling on the remedy for Google's search monopoly that will involve the divestment of Chrome, ushering in a new era of competition on the web. ®