Piracy may actually be aiding a minority of iPhone developers, the business development head of Tapulous suggests. Speaking at the MIDEM music conference in Cannes, Tim O'Brien notes that of the 2.5 million downloads of Tap Tap Revenge made in the game's first two months, roughly a million were pirate copies. Because gamers can now buy add-on songs, however, the extra users are helping Tapulous' profits.

"We've started running ads to the pirate users more aggressively," O'Brien adds. "Some of those users, because we sell virtual goods, have become high-volume users." Tapulous now has approximately 25 million users, and is in fact claimed to have been profitable since June.

Another iPhone developer, Shazam, has likewise noted high income from in-app marketing. The company's self-named service is now said to be identifying about 2 million songs every day, of which 13 percent -- about 260,000 -- are being translated into track purchases from affiliates, including Apple's iTunes. The company has had over 50 million users in total, and is said to be gaining 750,000 new ones each week. A new premium version of Shazam, Encore, has allegedly had no instances of piracy to date.