My theory is based on personal desire, and some early and very fake images of the iPhone 3G: video calling. A major desire for many users has been the ability to record video. If they give the chance to record it, they would also be pressured to let you send it to friends via email. But why stop there? Why not add a front facing camera and let users video call, simultaneously using their data connection and their mobile minutes?

Of course, these may once again prove to be pipe dreams...