Cookies and Cohorts


Article from Issue 246/2021

Is the web changing before our eyes? We in tech media certainly talk about change all the time. (One could argue that the whole point of tech media is to talk about change.)

Dear Reader,

Is the web changing before our eyes? We in tech media certainly talk about change all the time. (One could argue that the whole point of tech media is to talk about change.) And of course, big tech companies are always on the message of change. In all my years in the business, I don't think I've ever read a press release that said "Nothing happened! Everything is still the same!"

When you look at how far the tech world has come over the last generation, it would be fair to say that things must be constantly changing, or we wouldn't have come so far so fast. But given the constant rumble, it is prudent to wonder how much of that change is meaningful and real.

The big change we are hearing about this month is Google's plan to discontinue support for third-party cookies in the Chrome browser. Firefox and Apple Safari already disable third-party cookies by default, but the massive Chrome market share really tips the scales on a long-running debate about third-party cookies. It is fair to suppose that this change will mark a turning point in the business of advertising on the web.

An end to third-party cookies is certainly significant for web programmers, but will it improve the lives of everyday users? Will it mean more privacy? It depends on whom you ask – and what you call privacy.

Stopping third-party cookies (also called "tracking cookies") could certainly reduce the number of companies tracking you, but that doesn't mean you won't be receiving a similar share of targeted ads. You can bet that Google would not be taking flight with this new adventure if they didn't have a place to land. The company has been working on a new technology, which they call "Federated Learning of Cohorts" (FLoC), that they will likely rush in to fill the gap left by the sudden dearth of ad cookies. In the FLoC scheme, users are classified with other users who have similar interests (your cohort), rather than tracked individually.

It is still a little unclear how this technology will work in the real world, but it appears that an advertiser will say to Google, "Find me some users who like camping," and Google will put the advertiser's ads in the browsers of users who like camping, but the advertiser won't be able to place its own tracking cookies on the user's computer. Some within the advertising community think this new FLoC technology will make advertisers more dependent on Google, and antitrust authorities are apparently looking into the change as a potential threat to competition.

It is fair to say, though, that the interest of advertisers, and the complex issues of antitrust, are different from questions of privacy. It is highly possible that the new technology could be better overall for user privacy and still worse for a lot of the other things we object to in the open source community, like walled gardens and monopoly control. In that case, it is really hard to recommend it, but we can still keep watch and hope it will at least help to end the ridiculous excesses of third-party cookies.

To hear it from Google, FLoC is all about privacy. In fact, they have made it a central pillar of a larger strategy that they call their Privacy Sandbox. But then, you could ask, what does Google actually mean by privacy? Do they think it means something kind of like "incognito," because just so you know: Google is facing a $5 billion class-action lawsuit [1] over the so-called Incognito mode on Chrome browsers, which apparently is not so incognito – Google still tracks everything you do.

Joe Casad, Editor in Chief


  1. "Judge Rules $5 Billion Google Chrome Incognito Mode Lawsuit Can Go Forward" by Ron Amadeo, Ars Technica, March 15, 2021:

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