I understand where you're coming from, but touch changes how you interact with a device. I personally wouldn't want people judging my work based on their experience dealing with an interface I never designed for. Everything about the project screams fast and easy, and I'm cool with people doing fast and easy things for fun that don't work on all platforms.
1) Chalk is a paint app that uses touch (finger painting you might say). We've had paint apps that use mice for as long as I can remember (which is the Apple IIC). The translation between dragging your finger on a surface and clicking a mouse and moving it across the screen is very similar.
2) I wrote a little tutorial on this thread that shows how easy it would be to add mouse event support using the exact same jQuery event binding they are using for the touch events.
I actually suspect now that making the app iPad only is just to get more attention for 37Signals. There isn't a compelling technical reason for doing that other than marketing ploy.
"I actually suspect now that making the app iPad only is just to get more attention for 37Signals. There isn't a compelling technical reason for doing that other than marketing ploy."
Cynical. There's no ploy here, there's no big picture plan here re: releasing this just for the iPad. It was just easier. For a proof of concept, easy was the goal.
A couple of guys spent a few days messing around and this is what came out. We're really happy with it so we figured we'd share it with everyone else too.
We just went with the iPad because it was a lot easier to build it for a specific use case. We knew the exact dimensions, for example. We didn't have to think about how it would scale if the browser was wider or narrower. We could put everything exactly where we wanted it. It just works all the time since the iPad browser size is the same all the time.
We also didn't think it would be that fun to use with a mouse. Finger painting is more fun.
edited to add - and I don't own an iPad.