When Apple first launched App Tracking Transparency (ATT) as part of its iOS 14.5 and iPadOS 14.5 updates in 2021 there was much concern among ad companies. They worried that Apple had just singlehandedly ended their businesses, but two years later that doesn't seem to have been the case after all.
ATT is designed to help iPhone and iPad users choose whether they want to allow ad companies to track them between apps. With ATT and if users choose, ad companies no longer know when you use a gambling app and then also use a dating app, for example. That's vital information the ad agency loses, and that's a problem.
