Privacy concerns trump user targeting.
This one has been coming for a while. Apple flagged up its strategy six months ago, warning developers it would act against UDID tracking because of pressure from government and sections of the media.
The UDID is an alphanumeric string, unique to each device, that's used by developers, ad networks, analytics firms and so on to track a users app and site activity. It's a pretty important tool when so many content providers rely on ad funds to monetise their business.
But Apple is worried about UDIDs because, unlike web cookies, they can’t be cleared or deleted. And there are clearly ethical concerns around tracking users when they haven't given specific consent.
According to TechCrunch Apple is already rejecting apps that record UDIDs. It quotes developers including Fluik and Playhaven as having products declined.
It says two of the 10 review teams started doing blanket rejections of apps that access UDIDs this week. Next week, that will rise to four the ten teams, and keep escalating until all 10 teams are turning down apps that are still using UDIDs.
There are alternatives to UDID, but they are from multiple sources and what's really needed a some kind of standard that the industry can converge around.
Some firms are looking at including a permission form in their apps. But this would add an extra layer to the registration process, which would probably deter most consumers.
Others are pinning hopes on HTML5. UK-based buy-side ad specialist StrikeAd, for example, offers solutions that work off web cookies and the HTML5 datastore as needed, never reading or storing the UDID.
It says this approach delivers better results than UDID and means it can buy across mobile web and in-app.