How Apple’s ‘Ask App not to Track’ Prompt Helped TikTok’s War Against Facebook In April, 2021, Apple dropped a nuclear bomb on the world of online advertising. The company rolled out a new iPhone privacy setting called App Tracking Transparency, or ATT, that shows you, an iPhone user, a popup asking if you want to “Allow this app to track your activity across other companies’ apps and websites?” You have two options: “Ask app not to track” and “Allow.” The vast majority of people pick the former, which blocks apps from collecting certain data. Behind the scenes, the change caused...