See https://www.apple.com/legal/privacy/data/en/apple-advertisin... for the details.
Want to opt out of this? It's a OS-level setting in an obscure place, rather than what Apple requires from 3p apps.
Now, Apple isn't uniquely bad in the level of tracking they do. They're just the same as all of these companies are. The place where they are unique is the incredibly brazen self-dealing, using their control of iOS to boost their own tracking ad business over the competitors.
Citation? I'm not saying your wrong, but I haven't heard anyone make this claim before.
> rather than what Apple requires from 3p apps
For the sake of argument, even if we assume your prior claim is correct, this is still incorrect. Apple does not require third party apps to notify users or provide an opt-out mechanism from tracking user activity across the apps of a singular developer.
> We create segments, which are groups of people who share similar characteristics, and use these groups for delivering targeted ads.
> We may use information such as the following to assign you to segments:
> ... The music, movies, books, TV shows, and apps you download ...
> ... The topics and categories of the stories you read and the publications you follow, subscribe to, or enable notifications from ...
> ... Your name, address, age, gender, ...
> ... your App Store searches and browsing activity ...
> ... information stored on your device, such as the apps you frequently open ...
There is absolutely no suggestion there that these segments would be per-app. In fact, they cannot be per-app given some of the data they say they're using is only collected from places with no ads. That is not an exhaustive list by the way, but just representative examples provided by Apple. The only data they explicitly promise not to use for ads targeting is:
> No Apple Pay transactions or Health app data is accessible to Apple’s advertising platform