[shermozle]

There is in fact just such an identifier, it's called IDFV. ID For Vendor. It's shared between all apps from the same vendor, so your Facebook and Instagram apps know they're on the same device.

Apple used to be quite strict that you had to actually have advertising in the app to ask for the IDFA permission. That seems to have disappeared.

[varenc]

That's the one I linked to right? =)

https://developer.apple.com/documentation/uikit/uidevice/162...

[dep_b]

There used to be a global ID that was free to use, then they switched to the vendor ID. The IDFA never had anything to do with the vendor ID and has way more checks. To me the vendor ID isn't that big of a problem.