This is nice, but it probably isn't enough. Because T-Mobile has so many different phone models, a single app will only be able to reach a fraction of their customers.

But they don't all have different development environments. J2ME takes a huge chunk. There are thousands of existing apps, this just makes distro easier. Unless you were a big firm you probably weren't getting on the deck (and even then it wasn't easy).

If T-Mobile does it right it will be easy to target a specific platform (Sidekick, BlackBerry, etc) for apps that use features unique to certain platforms. No one has a real track record for doing it right, but there's always a chance.

It's the next step in phone companies bowing to Apple's vision. They copy Apple, they create something less capable of succeeding, Apple gains ground.

Still, I'd like to see how well they pull this off. As you said: getting it to work on everything is a little bit tricky.

It doesn't have to work on everything to suceed, as long as:

- There are large enough subsets to be worthwhile in their own right (e.g. J2ME phones, all Blackberry handsets, etc).

- Customers only see apps that will work on their phone. At present the mobile app industry is not helped by confusing customers before they even make a sale - not everyone knows what their device can do.

- Quirks that make porting between devices hard (e.g. wierd handset bugs, or carrier specific changes) are documented well. T-mobile are probably already doing this and it would cut down development time for ISVs.

I don't think it'll be a failure: I think they've got a good shot with this. What this does, however, is silence critics of Apple's App Store plan. When other companies pick it up, it gives Apple credibility.