Google’s controversial Federated Learning of Cohorts (FLoC) experiment now has a feature flag within Chrome Canary (the nightly build of Chrome for developers) that allows users to opt out.

In January 2020, Google announced its plans to discontinue support for third-party cookies in Chrome within two years. The first bits and pieces of the company’s Privacy Sandbox initiative started landing in Chrome in December 2020 with an initial flag to disable it. FLoC, Google’s proposed replacement for third-party cookies, began testing as a developer origin trial in Chrome at the end of March 2021.

In Canary, users can navigate to chrome://flags/#privacy-sandbox-settings-2 to find the Privacy Sandbox Settings 2 flag.

Relaunch Canary to save the changes. This will unlock the box that allows users to either reset their FLoC group or opt out of FLoC entirely. The new setting is available under chrome://settings/privacySandbox:

If the setting remains enabled, which is the default, Chrome will group users into cohorts based on recent browsing activity and then advertisers select ads for the entire group. Browsing activity for the individual is “kept private on your device,” but Chrome certainly has access that information by way of mediating the cohorts. Google notes that the trial is currently only active in some regions.

Users can also opt out of Privacy Sandbox trials on the same page. Current trials include the following:

• Advertisers and publishers can use FLoC
• Advertisers and publishers can study the effectiveness of ads in a way that does not track you across sites

Google has not specified how users would opt out of FLoC if the experiment is successful and moves forward. Organizations and site owners who are currently on the fence about it may go either way depending on how easy it is for Chrome users to opt out themselves.

“Instead of comparing FLoC to its predecessor, third party cookies, I feel it’s actually more like the Facebook Pixel – mostly in the sense that it’s controlled by a single surveillance capital company,” WordPress core contributor Roy Tanck commented on the trac ticket for the discussion. “FLoC may not be quite as nefarious, but I feel it should be something website owners consciously opt into.

“WordPress has always advocated for a free and open web, and FLoC appears to actively harm that goal. I think WordPress should take a stand against this, and do it now.”

A few others have chimed in on the ticket recently as other open source projects have started blocking FLoC by default. Plugin developer David McCan’s comment referenced analytics data published in early May suggesting that US users choose to opt out of tracking 96 percent of the time following the changes in iOS 14.5.

“There is no doubt that coming down on the side of user privacy vs user tracking is the right thing to do,” McCan said. “Which headline would we rather see? ‘By default millions of WordPress websites are allowing users to be tracked’ or ‘WordPress takes steps to block user tracking making millions of websites around the world safe to visit?’

“We already have a policy that opt-in by default tracking’ is not allowed in plugins hosted by WordPress. This is because we recognize the responsibility and benefit of protecting user privacy.”

During a live marketing event Google hosted at the end of last week, Jerry Dischler, vice president and general manager of Ads, addressed the recent privacy concerns surrounding FLoC.

“We’ll be using these [Privacy Sandbox] APIs for our own ads and measurement products just like everyone else, and we will not build any backdoors for ourselves,” Dischler said.

Dischler also reaffirmed Google’s commitment to moving away from third-party cookies.

“Third-party cookies and other proposed identifiers that some in the industry are advocating for do not meet the rising expectations consumers have when it comes to privacy,” he said. “They will not stand up to rapidly evolving regulatory restrictions; they simply cannot be relied on in the long term.”

Google bears the burden of reassuring advertisers that effective advertising is still possible as the company moves beyond tracking cookies. It is aiming to future-proof advertisers’ measurement of campaign performance with what it claims are “privacy-safe solutions.” The company is pushing hard for advertisers to adopt these new techniques, promising more actionable first-party conversion data.

Although consumer expectations have changed, FLoC may not be the answer to the need for a privacy-preserving advertising model. So far it looks like Google will have an uphill battle to gain more broad support from browsers, advertisers, and consumers.