Google has announced that it will be pulling the plug on Federated Learning of Cohorts (FLoC) and replacing it with Topics— a new Privacy Sandbox proposal for interest-based advertising, as per a blog post by Vinay Goel, Product Director, Privacy Sandbox, Chrome. “Topics was informed by our learning and widespread community feedback from our earlier FLoC trials, and replaces our FLoC proposal,” the blog read.
Google began working on FLoC as an alternative to third-party cookies which the Chrome browser will be phasing out by 2023. The company said that it will be launching a developer trial of Topics in Chrome soon for website developers and the ads industry that includes user controls.
“The final design of the user controls and the other various technical aspects of how Topics works will be decided based on your feedback and what we learn in the trial,” Goel said.
Consumer expectations around privacy have undergone a dramatic change in recent years as people become wary of big tech’s intrusion into their lives. Cookie-based marketing has become a multi-billion dollar industry and Google’s announcements are likely to impact them significantly.
Goel wrote that a user’s browser will determine a handful of topics that represent their top interests for the week as reflected by their browser history under Topics.
For example, it will devise categories like “fitness” or “travel & Transportation,” and keep them for only three weeks following which they will be deleted.
“Topics are selected entirely on your device without involving any external servers, including Google servers,” Goel revealed in the post. He explained that Topics will pick three topics, one topic from each of the past three weeks, to share with the site and its advertising partners when a user visits a participating site.
Google claims that Topics will allow browsers to give users “transparency” and “control” over their data.
“We’re building user controls in Chrome that let you see the topics, remove any you don’t like or disable the feature completely,” Google said.
Moreover, Topics will exclude sensitive categories, such as gender or race. There are nearly 350 available topics in its advertising taxonomy at present, according to the Topics API GitHub page. Google plans on adding anywhere from “a few hundred” to “a few thousand” eventually, The Verge wrote in its report.
How is Topics different from FLoC?
Google announced that it was experimenting with FLoC under its Privacy Sandbox initiative in a blog post last year. FLoC clusters large groups of people with similar interests. It hides individuals “in the crowd” and uses on-device processing to keep a person’s online history private on the browser.
FLoC attracted criticism for its “cohorts” because they combined online interests that could pose a risk of discrimination when classifying users, according to Monetize More, a tool that offers a suite of publisher monetization solutions.
Here are some of the key differences highlighted by the blog:
- Topics groups users into cohorts but not into interest topics;
- The new API gathers data on a weekly basis based on users’ online search history, and these topics are kept only for 3 weeks whereas FLoC gathers data about a user’s browsing habits and assigns them to a cohort based on the last week’s browsing data.
- Google FLoC used to share a cohort ID with advertisers and marketers while Topics selects the three most relevant topics and shares them temporarily with brands and sites.
Vinay Goel said that Topics provides users with a convenient way to see and control their data sharing because Topics is powered by the browser. He added that online businesses will not have to rely on covert tracking techniques, like browser fingerprinting, in order to continue serving relevant ads.
Why did the EFF label FLoC as “terrible”?
FLoC invited scrutiny from privacy advocates who warned that FLoC will allow advertisers to identify users with browser fingerprinting— a tool to gain specific information about a user’s device and browser, The Verge said. Many browsers, such as Brave, Vivaldi, Edge, and Mozilla, rejected participation, the report added.
The Electronic Freedom Foundation (EFF) called it a terrible idea that created new privacy issues, in its report.
“FLoC is part of a suite intended to bring targeted ads into a privacy-preserving future. But the core design involves sharing new information with advertisers. Users and advocates must reject FLoC and other misguided attempts to reinvent behavioral targeting,” the EFF urged its readers.
It listed down the following issues then:
- Fingerprinting: “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),” the organisation wrote in its blog.
- Cross-context exposure: The technology behind FLoC would expose two categories of users’ information to advertisers.
- Specific information about browsing history: “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,” the EFF cautioned.
- General information about demographics or interests: FLoC would make it easy for advertisers to identify that “members of a specific cohort are substantially likely to be a specific type of person”. “This means every site you visit will have a good idea about what kind of person you are on first contact, without having to do the work of tracking you across the web,” the EFF remarked.
- FLoC at odds with other civil liberties: The organisation warned that it would open new avenues of discrimination. “FLoC will use an unsupervised algorithm to create its clusters. That means that nobody will have direct control over how people are grouped together,” the EFF wrote in the post. “In a world with FLoC, it may be more difficult to target users directly based on age, gender, or income. But it won’t be impossible. Trackers with access to auxiliary information about users will be able to learn what FLoC groupings “mean”—what kinds of people they contain—through observation and experiment,” the EFF concluded.
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