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What the FLoC is FLoC?

Ryan Rakover, March 14, 2021

What you Need to Know about FLoC

  • Google’s announcement confirms that FLoC will only use “privacy-preserving technologies” such as anonymization or aggregation of data.


  • In contrast, other Ad tech players have been working on ID based solutions as ways to balance consumer privacy while maintaining personalization in advertising after cookies are depreciated.


  • In the pursuit of shaping the open web with a privacy-user-first centricity a combination of solutions is the best approach, for now. The success will be seen as the solutions are tested to show their ability to balance privacy as well as publishers and advertisers expectations.



Earlier this month, Google announced that it will be going forward with the proposal of its Federated Learning of Cohorts (FLoC) that is currently available for review and comments in Google’s Privacy Sandbox.

This announcement confirms that Google will be adapting its targeting methods to ultimately be separated from the User. This action follows the privacy-centric proposals suggested in light of the depreciation of third-party cookies. 

FLoC clearly states that the User is not followed online; instead, the behaviors are bundled and separated from personally identifiable information (PII), in contrast to the other ID – email hashed models as a protected id + behavior model.

Since Google’s announcement in January 2020, “Building a more private web: A path towards making third party cookies obsolete,” there have been significant efforts from around the industry to answer what the advertising targeting future would look like without third party cookies.

Across the many different solutions, a common thread is a focus on user privacy. The roads to user privacy are winding, but with the initiative to solve third party cookies, Google’s latest announcement gave us a few important points to consider. 

Third Party Cookies

Let us have a clear focus on what the focus is – Third-Party Cookies. Cookies are those small pieces of code that websites deliver to a user’s browser and remain as the User moves on. The User is tracked across multiple sites to target ads and measure how those ads perform. The use of cookies has always been questionable in regards to user privacy. Until Google’s initial announcement and launch of its “Privacy Sandbox,” cookies were the necessary evil in an ever-evolving marketplace.  

Google’s Privacy Sandbox set their goal as clear as they could: to build a solution that will protect User Privacy and that content remains freely available on the open web. The industry responded with developed open-source solutions, all looking to create a new privacy-centric advertising system while maintaining a commitment to the best consumer-focused experience. 

In the years to follow, the “Privacy Sandbox” documented the process of how to securely separate the User from their behavior. This separation would be a defining characteristic of the internet’s most effective alternative, The Trade Desks’ Unified ID 2.0. 

Google’s proposal, called “Federated Learning of Cohorts” (FLoC), would essentially put Users into groups based on similar browsing behaviors, and only “cohort IDs” and not individual user IDs would be used to target users. 

The most notable alternative to Google’s FLOC browser solution is The Trade Desks solution, Unified ID 2.0.  The Unified ID solution’s greater goal is that instead of separating the User from the behavior, the User has the freedom and protections of an anonymized ID. This ID accompanies the User behaviors but allows for personally identifiable information and unauthorized data to be protected. Also, the ID is then able to provide the User with controls. The User can log in and monitor and adjust the usage of their data by third-parties.

The Trade Desk has recently removed themselves from the Unified ID solution and handed responsibilities over to Prebid to manage. Prebid is an industry nonprofit focused on bringing greater transparency and efficiency to programmatic advertising through open-source solutions. The combination of this move and the solution’s flexibility makes it potentially the most User-centric option.

However, all of the above is not news. So, what did Google’s announcement tell us that we didn’t know? The first thing to note is that Google has stated that they will not rely on any identifiers they do not own and its effect on the identifiers in YouTube and Search marketplaces. 

The second thing of note is that Google’s announcement, which Google’s Ads team announced, not Chrome, will have no impact on email-based identity systems such as UID 2.0 and LiveRamp’s ATS. 

Clearly, the noise around privacy is really about competing solutions. Still, in reality, the Open Web’s future will consist of a combination of approaches: user logins, browser-based auctions, all while providing a privacy-centric user experience. 


For now, we see Google’s push for a better solution along with other industry initiatives. There is a chance to evolve the open web with the User protection at the center. 

Google is responsible for the current scramble to replace, reshape, and rethink cookies, but it also believes in its FLoC solution to provide the User with a privacy first web. 

Even though FLoC may not be an ideal privacy replacement for third-party cookies, it does represent an important first step in creating the digital framework for ensuring that User privacy is protected on the open web in the years to come.


Ryan Rakover is the head of our Trust and Safety efforts at Total Media. One of the things Ryan enjoys the most in his role as a Publisher’s strategic partner is the challenge of bringing policy from a place of rules and standards to delivering solutions to clients to improve their client’s bottom line.  Find Ryan on LinkedIn or reach him by email at ryan(at)totalmediasolutions(dot)com.