[matthewdgreen]

Palm, Blackberry and Windows PocketPC blazed the trail. iOS and Android were relatively latecomers that arrived with a more competitive product (iOS because it was much better than the previous generation, and Android because it borrowed the ideas from iOS and was free.)

[slenk]

Apple and Android both steal ideas from each other.

[basch]

capacitive touch and momentum scrolling were the differentiating factors.

Windows CE 4 was way ahead of iphoneOS 1, 5 years earlier.

[jjeaff]

I've never thought of momentum scrolling as a paradigm shift. But now that I think about it, it is a pretty amazing feature.