WordPress proposes blocking FLoC by default

A proposal that would block Google’s replacement for third-party cookies, Federated Learning of Cohorts (FLoC), by default across WordPress sites was put forth on Sunday. It is estimated that over 40% of all sites use WordPress (according to W³Techs), meaning that if this proposal gets implemented, a substantial share of browsing behavior may be hidden from Google’s ad-targeting technology.

UPDATE: Matt Mullenweg, CEO at WordPress’ parent company Automattic, has emphasized that a decision has yet to be made. “It is more correct to say there is a proposal from a WP contributor to block FLoC by default,” he tweeted.

How it will work. Under the proposal, FLoC would be disabled via the addition of a few lines of code that opt out WordPress sites from transmitting the user’s interest cohort to Google.

This functionality is not unique to WordPress; every programming language that powers websites typically carries a similar functionality. This would be relatively easy to implement if a website owner or developer wanted to do so, but if WordPress disables FLoC by default, that could be a large-scale blow to Google’s advertising capabilities.

Why the block was proposed. The WordPress proposal cites the Electronic Frontier Foundation’s article “Google’s FLoC is a terrible idea” and states that “placing people in groups based on their browsing habits is likely to facilitate employment, housing and other types of discrimination, as well as predatory targeting of unsophisticated consumers.”

In addition, the proposal also mentioned privacy concerns associated with tracking users and sharing their data “seemingly without informed consent.” For these reasons, WordPress is treating FLoC like a security concern, meaning that it can patch the next minor release (as opposed to holding off for the next major update, scheduled to become available in July) to block FLoC and back-port the patch to previous versions of WordPress as well.

Many WordPress sites postpone updating when a new, major release goes out because the update may cause compatibility issues with other parts of their site, so blocking FLoC in the next minor release as well as in previous versions of WordPress may mean that the FLoC-disabling code appears on more sites sooner.

WordPress joins a growing group of FLoC opponents. The Electronic Frontier Foundation’s arguments against FLoC have been echoed by players across different sectors of the internet: Chromium-based browsers Vivaldi and Brave are disabling FLoC and DuckDuckGo’s Chrome extension also blocks FLoC.

Google’s major rivals in the browser market, Microsoft, Mozilla and Apple, have not committed to blocking FLoC. Microsoft and Mozilla are evaluating various proposals (including FLoC) that would fill the void left by third-party cookies, according to The Verge, and Apple Webkit engineer John Wilander tweeted a similar position. Even so, it is highly unlikely that their browsers will ultimately support Google’s proposal.

Why we care. WordPress is the dominant content management system, so blocking FLoC by default could obscure a meaningful share of user behavior. That would, in turn, diminish advertisers’ ability to effectively reach potential customers via Google’s cohort-based targeting.

Google has said that it would end support for third-party cookies sometime in 2022. However, as FLoC moves forward to replace third-party cookies, more and more players are pointing out ways that it may fail to protect users, or ways that it may be anticompetitive. That 2022 deadline Google set for itself is now within view, but it seems like Google is the only one on-board with FLoC. As third-party cookies run out of time, the web will decide whether FLoC is successful or not — this proposal from WordPress can be considered a very important vote against it.