Last autumn, without much fanfare, along with the launch of iOS6, Apple quietly introduced a new identification technology called Identifier for Advertising. IDFA, or IFA, as it is often referred to, is a combination of characters that uniquely identifies a mobile device that runs iOS6 or above that lets advertisers recognize consumers anonymously.

IDFA was meant to offer an alternative – and now a replacement – to the common, and still widespread publisher practice of recognizing users through their UDID, the unique alphanumeric serial number that is assigned to every iOS device. After nearly a year of rumours and rumblings that Apple would ban apps that accessed UDID’s, there is now a hard deadline.

In a post to developers written on 21 March, Apple wrote: “Starting May 1, the App Store will no longer accept new apps or app updates that access UDIDs. Please update your apps and servers to associate users with the Vendor or Advertising identifiers introduced in iOS 6.”

Apple, itself, never intended for the UDID to be used for ad targeting. Moreover, tying UDIDs to ad-targeting has raised a number of privacy concerns, not least because consumers had no way to prevent this or control its use. IDFA, on the other hand, is not only specifically designed for targeting ads, but thanks to a recent update in iOS 6.1, consumers can now reset it at any time, thereby clearing their history of personalized ad-serving.

How IDFA works

When consumers use an app that runs advertisements, their presence on the app signals a call for an ad. The app sends the device’s IDFA to the ad server, allowing it to serve an ad targeted to that user. Given that most mobile devices are typically operated by only one user, you could say that IDFA identifies a user. But this is not 100 per cent accurate: user profiles are generated and stored server-side, and the IDFA is just pointing to them. An incoming ad request containing the same IDFA only helps to recognize a user; no further data other than this number and letter combination is being transferred, and especially no personal data. IDFA provides aggregate audience data that ad servers use to send targeted ads to consumers.

From a publisher’s point of view, IDFA can be thought of as anything from an opportunity to a drawback – depending on whether or not the consumer has activated it.

Previously, different advertisers used proprietary solutions to personalize their ad delivery – therefore mutually spoiling customer-oriented ad delivery, and this still happens. The more publishers utilize this new, standardized identification feature, the better the quality of targeting and personalisation will be for all.

Moreover, consumers often use more than one app, and different ad-supported apps – more likely than not – would rarely use the same ad network. Now, with IDFA, for the first time ever, cross-app user recognition – even if both apps use different ad-serving platforms – is now possible, opening up exciting new possibilities for marketers: target a user in one network – re-target him/her in another.

On the downside, the opt-out was given for personalized advertisements – not to be confused with a complete opt-out from all ads, that is, a consumer opts out of receiving targeted ads, not out of blocking them. This can potentially be misleading, and consumers might opt out without fully understanding the consequences: targeted ads are better than non-targeted ads; this goes for both customers and advertisers.

Room for improvement
The IDFA goes some way to partly cleaning up the uncontrolled and prolific growth of user identification technologies, but it also offers an easy way to opt out from submitting valuable information to ad networks. Things like conversion tracking or re-targeting can now rely on a robust mechanism. In the future, it would be helpful if IDFA is made accessible for mobile browsers as well. This would help overcome many of the challenges around user identification, and improve targeting across web and app.

Focusing user recognition entirely on the IDFA also means giving the consumer the option to easily turn it off any time. But this feature is only available for iOS 6 and above, meaning that not the entire installed base of iOS has access to it; the audience is limited to those iOS users who have upgraded to iOS 6.0 and beyond.

For the moment, however, with a hard deadline in place, the most pressing task for publishers is to check immediately whether or not their advertising partner still uses the UDID for identification purposes. Should that be the case, it will prevent them from being able to keep their published app up to date in Apple’s App Store.

Christian Ruck is product & research manager, mobile, at ADTECH