Time was a developer could call the UDID (unique device identifier) for your iPhone, iPad, and iPod touch and do with it what they would, from beneficial things like keeping your data allocated to you, to evil things like tracking you and your behavior for advertising and giggles. Now with iOS 5 beta 6 Apple aims to make it no longer so.
Deprecated in iOS 5.0
An alphanumeric string unique to each device based on various hardware details. (read-only) (Deprecated in iOS 5.0. Instead, create a unique identifier specific to your app.)
Which means devs will have to find a way around it, though according to TechCrunch some reckon Apple might not cotton to their own rules when it comes to first party services like Game Center and iAd:
“I guarantee Apple will not stop using UDID,” predicts one mobile industry CEO. If Apple does continue to use UDID for itself but denies it to developers that would be an “extremely lopsided change.”
For those concerned about end user privacy, this change will no doubt be welcome. For those who care more about convenience, it could cause some frustration. If the language makes it into the final release, that is.