• by Wendy Davis  @wendyndavis, April 3, 2012

TRUSTe is unveiling a new tool that mobile companies will use to target iPhone and Android users, while also enabling consumers to opt out of receiving in-app ads targeted based on their activity.

To accomplish this, TRUSTe is offering app developers access to a software development kit that will place an identifier -- which it calls a Trusted Preference Identifier -- on users' devices. App developers also will employ that identifier to recognize and target users. If people opt out of receiving targeted ads, that information will be tied to their identifier.

 Mobile companies will be able to access TRUSTe's database of Trusted Preference Identifiers and determine whether users have opted out; if so, the mobile companies won't serve targeted ads to those users.

Companies that have already indicated they will use the tool, called TRUSTed Mobile, include Electronic Arts, HasOffers, Human Demand, InMobi, JiWire, Medialets, Millennial Media and Nexage.

In the past, mobile companies were able to track iPhone users through their devices' 40-character identifiers known as UDIDs (unique device identifiers). Some mobile ad networks allowed people to opt out, but the process required them to write down their 40-character UDID and submit it to the network.

Apple recently began limiting developers' access to UDIDs, which has left mobile companies seeking alternatives. A few of the options to emerge -- such as tracking iPhone users based on their MAC addresses or their phones digital fingerprints -- are seen as privacy unfriendly, largely because people have no easy way of deleting a MAC address or digital fingerprint.

TRUSTe CEO Chris Babel says that consumers who install the identifier can later effectively delete the data associated with their devices by "renewing" or "revoking" it. Consumers who "renew" the identifier will receive a new one that maintains their opt-out preferences, but isn't tied to their old identifier -- and, therefore, can't be linked to cookie-like data previously associated with their devices.

People who "revoke" the identifier will simply receive a new one that doesn't include information about their opt-out preferences -- similar to what happens when consumers delete all desktop cookies, including opt-out cookies.

Jules Polonetsky, co-chair and director of the think tank Future of Privacy Forum, praised the tool for giving consumers an easier way to opt out of in-app ad targeting than submitting UDIDs to ad networks. "By providing a clickable mobile opt-out, TRUSTed Mobile ads makes consumer choice much easier," he says.