Apple's App Tracking Transparency

Identifier For Advertisers (IDFA)

Every Apple device contains a unique identifier called an Identifier for Advertisers (IDFA) that collects information from its given user without disclosing personal identification information about the user themself. By tracking information about the actions and behaviors of the user across the device rather than the personal information provided by the user, Apple is able to uphold a level of anonymity about the specific identity of the user of each device.

Even with the identity of the user anonymized, advertisers are still able to gain mass amounts of information through the IDFA to produce customized advertising to the user. Companies are not able to learn specific information regarding the user, but they are able to aggregate the data to still directly market towards each user.

When the IDFA was originally created, Apple automatically opted users into sharing their collected app data with the IDFA. Users could choose to opt out of sharing their information by going into settings and turning off this sharing option. With the new iOS 14 update, App Tracking Transparency automatically opts users out of sharing this information rather than automatically opting them into the IDFA. This feature was always technically optional, but the new release makes users choose to share, rather than making users choose not to share.