Google is experimenting with an ad targeting technology called FLoC (pronounced "flock") that uses Chrome to analyze users' browsing histories and place them into groups with similar browsing habits. The tech giant says FLoC, which stands for a “Federated Learning of Cohorts,” could replace third-party cookies, and says “advertisers can expect to see at least 95% of the conversions per dollar spent when compared to cookie-based advertising,” for reaching in-market and affinity audiences.
“Instead of understanding browsing behavior or interests at an individual level, the intent here is to have groups of users who would have similar interests.”
Chetna Bindra, group product manager, user trust and privacy at Google.
The advancement comes as Google, Apple and other companies scramble to find a replacement for third-party cookies, and as users push for more privacy on the web through
new regulations like the CPRA.
FLoC uses an algorithm built into the Chrome web browser that observes what websites a user visits. The algorithm then uses that browsing information to put the user into a cohort, a group of thousands of other users with similar browsing habits. That cohort can then be used by publishers and advertisers to serve up targeted ads.
Google says the FLoC proposal shares only the cohort group to advertisers, and does not share any information the browser uses to arrive at the cohort, like a user’s browsing history. The groups are also large enough to make identifying an individual unlikely, and a cohort can be updated over time as the user browses the internet.
On the other hand, According to Bennett cyphers, FLoC is meant to be a new way to make your browser do the profiling that third-party trackers used to do themselves: in this case, boiling down your recent browsing activity into a behavioral label, and then sharing it with websites and advertisers. The technology will avoid the privacy risks of third-party cookies, but it will create new ones in the process. It may also exacerbate many of the worst non-privacy problems with behavioral ads, including discrimination and predatory targeting.
Indeed, for FLoC to be useful to advertisers, a user’s cohort will necessarily reveal information about their behavior.
There’s another really important issue. What if you’re searching and reading up on a sensitive subject?
Say you’ve been a victim of domestic violence, or you’re worried about a health condition. Could you be assigned to a cohort that potentially reveals that to an advertiser?
It’s certainly possible, but Google will exclude certain topics from inclusion. It has a
list of things that can’t have personalized ads run against them.
The problem is that there is an algorithm in charge of managing this. While it might discard any pages that contain keywords, it may not be able to do this effectively for everything.
Another issue is fingerprinting. Browser fingerprinting is the practice of gathering many discrete pieces of information from a user’s browser to create a unique, stable identifier for that browser. EFF’s demonstrates how the process works: in a nutshell, the more ways your browser looks or acts different from others’, the easier it is to fingerprint.
Google has promised that the vast majority of FLoC cohorts will comprise thousands of users each, so a cohort ID alone shouldn’t distinguish you from a few thousand other people like you. However, that still gives fingerprinters a massive head start. If a tracker starts with your FLoC cohort, it only has to distinguish your browser from a few thousand others (rather than a few hundred million).
Google cautions that the technology is still in an early stage and is only one of several other solutions meant to comply with the Privacy Sandbox, a set of proposals for ad tracking while preserving user privacy. However, Google says FLoC is “at the leading edge” of the current proposals, says Bindra.
Will FLoC be adopted by other browsers?
Google hopes that the idea of FLoC will be taken up by other browser makers. It’s unlikely that Apple will accept it for Safari. Microsoft and Firefox will have to make their own decisions on its acceptability.
It’s worth pointing out that of the main web browsers, Safari and Firefox already both block third-party cookies by default. Edge and Chrome (in its current version) do not.
