What is Google FLoC?

Federated Learning of Cohorts(FLoC) is the new web tracking technology after Google decided to phase out third-party cookies which are already being implemented. Almost everyone knows a major share of Google revenue comes from its ad business and its free services like Google Analytics, Google Ads, Google Search, Blogger, YouTube, and its most popular browser Chrome all provide valuable data to Google to keep its business running. According to Google FLoC is privacy first technology then why are many researchers and technologists are opposing it. Even Chromium-based browsers like Brave, Valvidi and Google Private Search competitor DuckDuckGo disabled it. This article gives a basic understanding of What FLoC is, and it’s up to you to decide how many Google statements about FLoC are true.

What are Third Party Cookies?

Cookies just contain some data about your interaction with some websites. Cookies may contain request-id when websites use CDN’s, they are helpful for session management, can store user preferences, and apply them automatically when you visit the same website again. Cookies are very helpful if used correctly.

Third-Party Cookies are the cookies placed by third-party domains when we visit some website. For example when you visit a website that shows ads like geeksforgeeks.org the cookies placed by geeksforgeeks.org are called First Party Cookies while cookies placed by googleadservices.com are called Third-Party cookies. These are cookies placed by domains/websites even when we are not on their website.

For many years Ad businesses used these third-party cookies to track users across different websites to give them more personalized ads. But along with them, Privacy based browsers like Firefox and Brave started to tighten the placing of third-party cookies, even some DNS services like NextDNS effectively block the resolution of these party domains. So Google realized they have to find another way to keep its business running and one of them is the FLoC.

What are Cohorts and FLoC?

Cohort means a Group of People with similar interests. People who like movies are a cohort, people who play cricket are a cohort. Google’s idea behind Federated Learning of Cohorts essentially means serving ads based on the cohort user belongs to. Chrome users are assigned to a Cohort according to their browsing patterns. Every Chrome browser has a unique cohort id generated while assigning to a cohort. From Google’s words “We started with the idea that groups of people with common interests could replace individual identifiers, This approach effectively hides individuals ‘in the crowd’ and uses on-device processing to keep a person’s web history private on the browser.” Cohorts are updated weekly. Websites need to choose what type of ads to serve to users based on the cohort. Until now its looks better than why many aren’t happy with it.

Why is FLoC not having a good start?

Google already started testing FLoC in March 2021, Many users are already being added to their cohorts. But apart from Chrome, almost all the major browser vendors opposed the implementation of FLoC, Digital Rights Non-Profit Electronic Frontier Foundation (EFF) also in the list of opposing it. The major reason is that FLoC is new there is no guarantee that it will be used as proposed. One of the major drawbacks of FLoC which Google admitted resolving is Browser Fingerprinting. It refers to mapping different pieces of information to create a complete profile of a person. Suppose if you have been moving few different cohorts but similar in nature like from Baseball cohort to Cricket cohort to Football cohort, the ad business can easily conclude that you are into sports. Cohorts may also reveal more information about you which can be lead to more targeted advertising. 

Specific information about browsing patterns. Trackers may be able to reverse-engineer the cohort-assignment algorithm to determine that any user who belongs to a specific cohort probably or definitely visited specific sites. Google also hasn’t talked that much about how sensitive cohorts like representing health searches, Fake information, biasing based searches will be handled.

FLoC is new and is far from being perfect but it’s up to you to decide, if you want to disable FLoC, Go to Privacy and Security in your Chrome Settings and turn of “Privacy Sandbox” this will disable FLoC in Chrome. If you are using other browsers than Chrome you are already Good.