Apple has also cracked down on advertisers, limiting their ability to track users as they browse the web. The company introduced last year Application tracking transparencyIt allows users to block app tracking, a decision that has alarmed Facebook and other big advertisers.

Since marketers rely heavily on cookies to target ads and measure their effectiveness, Google’s privacy proposal has raised concerns that it will cement the company’s dominance in the industry, since Google already knows a lot about users’ interests and habits. Privacy experts fear that the groups may expose users to new forms of tracking.

Google’s proposal also attracted the attention of regulators. The European Union said it was investigating the plan as part of an investigation into Google’s role in the digital advertising market. Last year, Britain’s Competition and Markets Authority reached an agreement with Google to allow the regulator to review changes to trackers in Chrome as part of the settlement of another investigation.

Google said the threads will address some of the concerns privacy advocates have raised about FLoC, preventing other covert tracking technologies. It aims to preserve user privacy by dividing your audience into larger groups.

Google said there are tens of thousands of potential groups in the previous plan, but it will reduce the number of topics to less than a few thousand. The company said that users will be able to see which topics are related to them and remove them if they want.