I don't think there's much problem with Apple providing a unique ID to an app — the problem is that Apple is providing a unique ID that's universal to every sin

I don't think there's much problem with Apple providing a unique ID to an app — the problem is that Apple is providing a unique ID that's universal to every single app, making it far easier for some very troubling data correlation and identification by third-party services. Just a simple hash of the UDID and an app's bundle ID would probably be sufficient. Edit: Now that I think about it, it would probably need to be a salt that Apple keeps privately — since bundle IDs are known and UDIDs are fixed-length, those that really wanted to could brute-force UDIDs out of the resulting hashes.