(Pocket-lint) - Traditionally, when you browse the web, your activity is tracked by cookies. Simply cookies are bits of data, downloaded to your device and then used to track your movements around the web. 

This is how you see adverts on various websites that are tailored and relevant to your interests. Cookies, therefore, make you more likely to buy and ensure you see relevant adverts. 

They do have some privacy concerns though - with third-party cookies being widely thought to know too much about you and your habits. 

Google's Federated Learning of Cohorts is a privacy-preserving technology designed to replace third-party cookies to make your data anonymous. But how? Read on to find out.

What is FLoC?

Federated Learning of Cohorts (FLoC for short) is an undertaking by Google to eliminate third-party cookies and replace them with something more anonymous. 

FLoC is still an advertising technology but instead of tracking your individual movement on the web, it's designed to cluster the user into large groups based on interest. 

The idea here is to group users together and keep an individual user's web history private on the browser instead. 

Google claims that "... advertisers can expect to see at least 95% of the conversions per dollar spent when compared to cookie-based advertising." In other words that the system is still effective, but that it will also offer enhanced privacy for the user. 

How does FLoC work?

With the technology implemented, your web browser (only Chrome currently) will use machine learning algorithms to work out grouping based on the sites you visit. 

The only information that's then uploaded is the cohort you're assigned to based on the sites you visit. The cohort grouping may change over time as your browsing habits do, but your data will still remain private. 

All sites that you visit when not browsing in incognito mode will be included in the cohort calculation in order to establish your relevant group. 

Within those groups, there will be thousands of other users with similar interests. Though it is worth noting that the guidance says that cohorts that might reveal sensitive categories such as race, sexuality, or medical history will be blocked from being used. Which again should protect the end-users privacy but also prevent inappropriate grouping. 

Advertisers will then use your grouping in order to serve you relevant adverts. 

FLoC is coming as part of newer versions of Chrome. With Chrome 90's release including controls for the so-called Privacy Sandbox, which gives users control of settings but more will come in the future too. 

Could FLoC still be a privacy problem?

The official guidance and explainer on FLoC notes that there are some instances where the tech could be abused and user data revealed. 

It's noted that:

"Sites that know a person’s PII (e.g., when people sign in using their email address) could record and reveal their cohort. This means that information about an individual's interests may eventually become public."

This is said to be less of an issue than currently, where your exact browsing history could be linked to your email address or other personally-identifying information, but it's still not ideal. 

What others think

DuckDuckGo doesn't think much about Google's plans and agrees with the Electronic Frontier Foundation (EFF) that FLoC is bad for privacy

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DuckDuckGo's search engine is blocking FLoC by default, the company also has a Chrome extension to help you block FLoC if you're worried about it. 

The Electronic Frontier Foundation (EFF) has created a website called Am I FLoCed? Which is designed to tell you whether your Chrome browser has been turned into a guinea pig for Federated Learning of Cohorts and let you know what your Cohort ID is. 

Meanwhile, Microsoft has disabled FLoC tracking in Microsoft Edge. Wordpress also suggests that FLoC should be treated like a security concern and it is adding code to disable FLoC on its blogging platform. 

Time will tell how the web as a whole accepts it. 

Writing by Adrian Willings.