Yes. IDFA's full form is "The Identifier for Advertisers" which is generated by OS itself. Think of it like a proxy of IMEI number itself (back in the old days IMEI itself was used instead of this).
All of the Apps get the same ID and that's how your "persona" graph is constructed.
Sidenote: One of the bets people are making with this change is that now free apps will start forcing you to signup (via email/mobile number) which will be used to construct this "persona" graph again because who has time to create new emails for these purposes.
All of the Apps get the same ID and that's how your "persona" graph is constructed.
Sidenote: One of the bets people are making with this change is that now free apps will start forcing you to signup (via email/mobile number) which will be used to construct this "persona" graph again because who has time to create new emails for these purposes.