Mobile apps are all the rage these days in the music industry circles and justifiably so. Sales of traditional console-based music games have dropped significantly, but music and gaming still do make great partners. And while people’s interest in paying for music is waning, paying for apps is a growing phenomenon. Universal Music Group’s newly launched “Six-String” music app for iPhone/iPod touch is a case in point. The question now is not whether the industry should invest in iPhone apps but what is the best way to do so.

For an answer to that question let’s examine the current most successful paid music app on iTunes – I am T-Pain. “I am T-Pain” allows users to record their version of the T-Pain song into iTunes and auto-tune it. Here’s why I think the app is successful –

The game is engaging to all levels of gamers and music fans – Most people can sing an out-of-tune song into a micro phone. As the app is not very challenging it attracts a wider range of individuals and than the instrument simulation apps such as Six-String would.

It allows users to share the experience and be social – Once you have auto-tuned your voice you can upload it to your Facebook, MySpace page or email it to your friends. You can also check out the best auto-tuned songs that others have uploaded. Unlike other social games, however, this app is not really about competition and shows that music apps don’t have to be.

It generates in-app purchases – If you are done with the 6 songs that came with the app you can always buy more for 99 cents. Although the latest version of the app lets you use your own library reducing the incentive to purchase songs in the app. But the comments posted by users on the site suggest that the auto-tuning experience is better with songs in the app.

It's blurring the distinction between what is promoting what – People aren’t necessarily engaged with app for the music. Here’s a comment from one of the reviewers on iTunes – “I DON’T EVEN LIKE T-PAIN AND I <3 THIS APP!!!. This app is my new recording device…” This raises a bigger question – Is the music the end product for the customers or the game? Do they buy the music because they’ve played the game? Or do they play the game because they like the music? This isn’t just about music games, this is one more step on the path to freeing music from the chains of the album and reinventing itself in a diverse portfolio of interactive media formats that are relevant for the digital age.

People will get bored and move on to the next new thing in a short period of time. But that’s just the nature of social gaming. It behooves the industry to move fast to introduce new apps and keep the upgrade cycles short.