Identifier for Advertisers

Apple's Identifier for Advertisers (IDFA) is a unique random device identifier Apple generates and assigns to every device. It is intended to be used by advertisers to deliver personalized ads and attribute ad interactions for ad retargeting.[1] Users can opt-out of IDFA via the "Limit Ad Tracking" (LAT) setting (and an estimated 20% do).[2]

Starting in iOS 14.5, iPadOS 14.5, and tvOS 14.5, users are prompted to decide whether to opt-in or out of IDFA sharing before apps can query it. This choice can be altered in Settings.[3][4] In May, 2021, Verizon-owned advertisement analytics company Flurry Analytics reported that 96% of US users opted out of IDFA sharing.[5]

  1. ^ Aridor, Guy; Yeon-Koo, Che; Hollenbeck, Brett; McCarthy, Daniel (2024). "Evaluating The Impact of Privacy Regulation on E-Commerce Firms: Evidence from Apple's App Tracking Transparency". CESifo Working Paper No. 10928.
  2. ^ "Identifier for Advertisers (IDFA) | Meaning". www.adjust.com. Adjust GmbH. Retrieved 2020-12-25. roughly 20% of iOS users cannot be tracked using the IDFA because they have enabled LAT.
  3. ^ Krasnoff, Barbara (2021-04-26). "How to use iOS 14.5's new app tracking blocker". The Verge. Retrieved 2021-04-27.
  4. ^ "User Privacy and Data Use". Apple Developer. Retrieved 2021-04-26.
  5. ^ Axon, Samuel (2021-05-07). "96% of US users opt out of app tracking in iOS 14.5, analytics find". Ars Technica. Retrieved 2021-05-08.