But few have been asking these question since mid 2020 when Apple started a war against Data Collection. No one seems to care much.
[1] https://twitter.com/benedictevans/status/1387130787510751239...
[2] https://www.ben-evans.com/benedictevans/2021/5/13/apples-ads...
[3] https://www.ben-evans.com/benedictevans/2021/8/27/understand...
So geo-targeting, and targeting via fine-grained (5k people in the same segment) advertising profiles built from data such as your age, name, address, gender, what other apps you've installed, what content you've consumed in Apple products, etc.