First of all, lets get it right: T-Mobile’s App Store will not be a single store like Apple’s. Instead, it will be a chain of stores, each of which will cater to a specific device. You can’t really expect very different devices, running on very different platforms ranging from Android to Windows Mobile to just about anything, to have any soft of compatibility in common.

The software aside, even the hardware is going to pose some really daunting challenges. With each device has sporting different graphics capabilities, different processing powers, a variety of screen resolutions and screen sizes, even displaying the app store conveniently for people will be a daunting task. 

And yes, the total number of customers may look like some 31 million  (compared to Apple’s 10 million by the end of 2008) but in fact, since apps can only be developed for specific devices, the actual customer base for any app will simply depend on the number of those devices in use.

Naturally, developers are going to pick and choose. And I wouldn’t be surprised if they pick Android, and occasionally choose Windows Mobile even. The feature phones under T-Mobile are unlikely to be very popular among developers. After all, people who buy a feature phone generally do so either because they don’t want to spend too much on a phone, or because they don’t want anything too complicated. In either case, I don’t quite see how the launch T-Mobile’s app store is suddenly going to change their spending or usage habits.

For developers, since developing the same app for different devices will mean about as much effort as developing an entirely new app, (zero compatibility between Android and Windows Mobile, for example) there is little advantage for them putting in the energy to develop the same app for more than one platform. Even in terms of marketing and brand-building, moving from one store to the next is unlikely to get the developers much brand recall or loyalty: you might like something on your Samsung phone, but as a Motorola user, I’m  unlikely to come across, and cannot be sure that it will work equally well on my phone too.

And what sort of apps can we expect to see anyway? Since Java is common to most of these devices, one can see a large number of Java apps. Reasonable (not great) gaming potential, but not much functionality. And the charges to users for these apps are going to be based on bandwidth usage, so you can forget seeing Pandora on AOL Radio or Flickr, even.

Lots of questions, but the biggest of them all is whether T-Mobile is  equipped to handle this in the first place. Quite unlikely. Apple, which is an experienced hardware and software company, which knows all aspects of its own OS and its SDK, as well as every last thing about the hardware involved, has encountered teething problems with its App Store launch–problems they’ve had to lose sleep over, in some cases. What are the chances that a carrier that knows neither the hardware nor the software involved, will succeed at such a daunting task?

But let’s be clear what I mean by failure in this context. It is highly unlikely that T-Mobile will launch its app store, wait for developers to join, and then after a few months wind up the show, conceding that the move was a failure. In fact, if the failure is so quick and clean, T-Mobile should consider itself lucky. What will happen instead is that there will be fanfare, the initial developer interest, some bad and some good apps released to the platform. Then in a few months, developers will realize that there are just too many problems to contend with, both technical as well as in terms of the way T-Mobile is handling the whole project. Developers who’ve put in too much effort or money will stick around, but new ones will not join.  Eventually people will forget about this app store, but T-Mobile will be stuck with the task of maintaining it, of adding it to their billing system, of making sure the technology is still in place and free of glitches, and so on. In short T Mobile will be stuck with all the things a carrier would rather not be bothered about.

But one thing is clear: if the iPhone made other device makers sit up and take notice, the App Store is doing to the same to carriers. Apple has truly shaken up the industry, The closed deck model, where you took the mobile device out of its box, already packed with all the features and software it would have, is set to be phased out in the very near future.