It's not news that Apple is phasing out its UDID unique device identifier.

The company officially listed it was deprecating the technology for iOS 5 in August 2011.

Since then there has been ongoing titbits concerning how quickly Apple is encouraging and/or forcing compliance.

Moving the goalposts

The problem is everyone from developers and publishers to ad networks and analytics companies rely on UDIDs to provide accurate numbers when it comes to app activity on an iOS device.

Obviously, if multiple people are using an iPad, this data is muddied, but it's the best option and everyone has access to it.

Now, however, Apple is stepping up its pace, informing key publishers and other clients that they have to come up with another way of tracking users, very soon.

Plan B

Of course, this is possible. Indeed, it's a necessity for everyone.

But it will be less accurate - being based on a per app or per ad network basis - something that will break industry-wide comparisons between companies on iOS as everyone will be using different systems.

Perhaps that's part of Apple's plan. There's the sneaky suspicion its unsuccessful iAd network may end up with better data than the rest of the industry, giving it an inbuilt advantage in terms of targeting users.

The fightback

Yet there's also possibility that by forcing companies to come up with something different, Apple may end up forcing them to create a cross-platform industry standard - however lowest common denominator.

It's an interesting proposition, although not one that seems to be gathering momentum; at least in the sense anyone will talk openly about.

"We're looking at alternatives and testing them," said InMobi's director of business development, Limvirak Chea.

"You have to be ready with an alternative, but we're not saying anything officially at the moment."

Fragmented view

NASDAQ-floated Velti is working on its own finger printing technology, which it hopes will provide 95 percent accuracy compared to UDIDs.

It also expects this technology will give it better view of individual user activity across their different devices; useful in a world where people have smartphones, tablets of various hues, and iPod touches.

Indeed, the shift away from UDIDs could, in the longterm, see a wider industry move to tracking users as individuals (anonymous ones, of course) as they move through the app ecosystem, rather than being tied to what's going on with individual devices.

Certainly specific parts of the industry are highlighting their solutions, while on the gaming side, this will clearly play into the hands of platforms such as GREE, DeNA's Mobage, PlayPhone, Scoreloop etc, who can get players to sign into their systems.

It's something the likes of Tapjoy, Fiksu, GetJar and W3i are also playing around with - not to mention Facebook's push in this area.

Brass tacks

Meanwhile, other ad networks are taking a more aggressive approach.

One told us at Mobile World Congress, "Apple will eventually play ball when it comes to UDIDs".

The reasoning is that if advertisers can't properly target their ads on iOS, yields will drop, and developers and publishers will focus more on Android.

Although, given iOS' comparative ease in terms of monetisation for paid and free-to-play games compared to Android, which is more of an ad-friendly platform, maybe that's a situation Apple would be happy with.