Apple has already provided a few clues as to what it's going to put on the plate for developers at WWDC. One change that's unlikely to be touted at the keynote, or even the entire conference, could prove to be the most important for app writers: an alternative to the UDID (Unique Device Identifier) that Apple started phasing out a year ago. If Wall Street Journal tipsters are right, the hardware-specific ID will be replaced with tagging independent of any one iPad or iPhone, such as a number sequence. The system as it's teased would let developers track user behavior and improve their apps without spooking users worried that Apple, or someone else, might snoop over their shoulders by linking a UDID to the owner. It sure sounds like a remedy to mounting privacy concerns to us, although an unveiling supposedly due within the "coming weeks" raises the possibility that the new ID won't show its face until after the programming hordes have already left San Francisco.