Some misconceptions here. There are analytics and demographic research companies that actively buy and sell this data for very large sums of money. This sound

Some misconceptions here. There are analytics and demographic research companies that actively buy and sell this data for very large sums of money. This sounds believable - people are buying and selling my valuable data! - but it's completely mythical. (I wish it were true, since I'd be a lot richer.) Behavioral targeting data from application usage isn't worth a hell of a lot, especially since it can't easily be linked to profiles on the mobile or broader web. Analytics companies don't buy data at all and have difficulty selling it, if they're even attempting to - there's not enough money in it to make it worthwhile. Demographic research firms have all constructed their own small panels with full user opt-in, and the other interested parties out there aren't paying very much. You can make a little bit of money off of usage data, but not enough to support a company. The UDID is currently the only way to track an advertising conversion from an ad in one app to the installation of another app. Well, it's currently the easiest, most reliable, and most user-friendly way - so it's the one everyone uses. The article itself goes on to mention some of the alternatives, so this is a curious assertion. [T]he prevailing attitude around Apple violations is “we’ll know it when we see it.” Workarounds that break the spirit of a rule are likely to be rejected just the same. It's just as likely that the services will continue using the deprecated but still available UDID call. If Apple decides to test for and police UDID usage or any other workarounds, they absolutely can, but that decision's up to Apple. If the subset of application developers important to Apple wants cross-application tracking, I suspect there will be a way to do cross-application tracking. We'll only know the real implications of Apple's UDID deprecation after iOS 5 is broadly deployed.