Apple is asking developers to stop using a tracking feature in apps.

From the WSJ:

Developers who write programs for Apple’s iOS operating system have been using a unique identifier specific to each device to gather personal data about users, in some cases creating detailed dossiers on how they use multiple apps. But Apple advised developers not to use that ID number, known as UDID or Unique Device Identifier, with a new version of the operating system that is expected to become available in coming weeks.

This is on the heels of a South Korean class action suit about tracking filed against Apple last week as well as ongoing controversy surrounding just how much your phone knows about you. This is a blow to advertisers who were using the system to target advertisements as much as possible. Some of those advertisers are concerned that the move might be Apple’s way of giving its own advertising network, iAds, an advantage. Privacy advocates are happy but say they will monitor exactly how this all plays out.