The FTC is asking Meta about Apple’s 2021 App Tracking Transparency policy that let users decide whether to let developers track their activity off-app to help serve more persoanlized ads. Meta warned investors in 2022 that it would result in a $10 billion revenue hit to its business that year. That’s presumably because when users are given an option to give Facebook and Instagram less data, at least a significant chunk of them take it. We don’t know exactly how many, though, since the judge sealed the courtroom to discuss internal metrics like how many people opted into the tracking.