Are mobile app stores the wave of the future or just another passing digital fad?

Berlin-based research group Research2guidance sees a bright future in the market, predicting that the worldwide smartphone application market will reach $15 billion by 2013. The company says the market has already reached $2.2 billion in the first six months of this year along, again based on worldwide figures. That’s on the back of 3.8 billion app downloads, compared to 3.1 billion downloaded for the entirety of last year.

The company points to the growth of not only Apple’s App Store, but also competitors such as Android, the Android Market and Blackberry’s App World. Future growth will be driven by specialty stores for specific applications such as those targeting business uses or healthcare functions.

The folks over at the Music Void meanwhile ask a few questions about the long-term viability of the space. They start out by questioning whether app owners will revolt once they discover they can’t bring their apps with them if they switch to a new phone, such as from an iPhone to an Android device. That seems unlikely as mobile subscribers have long left content behind on old phones (such as ringtones and games) when migrating from one device to another, and since the most popular apps are formatted for multiple platforms it’s not too hard to just re-download a useful app on the new phone.

The Music Void makes the argument that open app environments will thrive in the long-term for this reason, resulting in more churn off of closed environments like the Apple iPhone/App Store. Again, very unlikely. People made the same prediction about the iPod/iTunes ecosystem and that remains today the dominant digital music platform. Just look at the app activity on these different platforms. Sure Android is surging in growth as more and more phones come out featuring the operating system. But the iPhone remains the platform where the most activity takes place. App developers have an easy choice - develop to the platform with the most devices or the platform with the most likelihood that their apps would be used.

For a more in-depth discussion on application platforms and the future of the mobile app market, be sure to attend Billboard’s Mobile Entertainment Live: The Music App Summit Oct. 5 in San Francisco, where speakers like Motorola’s VP of software applications and ecosystem Christy Wyatt will be present to offer their insights.