Introduced by Apple in 2021, App Tracking Transparency (ATT) is a privacy feature that gives users greater control over their data. It requires apps to request permission from users before tracking their activity across other companies’ apps and websites for advertising purposes. ATT has been praised by privacy advocates and has had a significant impact on the digital advertising industry, though some developers have expressed concerns about the impact of ATT on their revenue streams.
This privacy-increasing guideline was introduced with the beta release of iOS 14.5, iPadOS 14.5, and tvOS 14.5, and continues in subsequent releases of Apple’s mobile and smart TV platforms. The AppTrackingTransparency framework shows users a popup asking for their permission to access their device’s unique identifier for tracking purposes.
As Apple highlights in their privacy policy and data use article:
Tracking refers to the act of linking user or device data collected from your app with user or device data collected from other companies’ apps, websites, or offline properties for targeted advertising or advertising measurement purposes. Tracking also refers to sharing user or device data with data brokers.
If people choose to opt out, advertisers and ad networks will not be able to see their IDFAs, a device identifier for advertisers. If people opt in, advertisers and ad networks will in fact see them. An IDFA is a unique identifier that allows companies to recognize a user’s device and track their activity across apps and websites. The goal of tracking an IDFA is to measure and analyze the performance of marketing campaigns.
You can check how many people opt in and opt out of App Tracking Transparency in Singular’s quarterly trends reports.