Killing SMS

As the comments to the article point out, it's not so easy. Carriers are complete arses to interoperate with.

This is not to say that this can't be a fantastic business - great barriers might mean that there's a mint to be made if you figure out a way around them - just don't underestimate the lack of cooperation from the carriers. That'll be your biggest showstopper.

The Truphone app is interesting. If you could do "paging" or something like SMS with it, it would be disruptive. Even though the iPhone doesn't allow background processes, having the push notification on your app icon would allow the user to receive a "page," find a Wifi connection, start up the app and call the person back.

I don't even think the network effects are that important. My girlfriend and I could use it to keep in touch with only each other without paying SMS fees during the day. Then we can tell another couple about it. Much the same happened with Skype and people using it to call their parents.

Can't send SMS with the iPhone SDK, so his auto-detection and fallback to use SMS will not work.

I've heard that Apple has canceled the push service, or limited it to one push per 15 minutes?

Android also comes with a nifty xmpp messaging system that could be used to replace SMS