[jordanthoms]

I don't see it the same way - Android's been behind the other smartphone operating systems in UI quality, and has had to iterate quickly in 2.x, 4.x and 5 in order to catch up. As they reach a point where Android has as good or better user interface as the competition (I think they're close to that now), the rate of change will most likely slow down.

[iaskwhy]

Also, it's a kind of new field for ergonomics and usability so all these changes (both hardware and software-wise) are something to be expected.

[72deluxe]

Whilst true to some extent, it isn't as new as we think. Window Mobile has been around for a very very long time and Palm OS preceded it with usable Palm Pilot devices.

[iaskwhy]

Although it's not obvious, I guess popularity as a lot to do with ergonomics and usability and their evolution so something will only continue to be pushed forward if there's enough people to actually use it. I don't know, I'm just thinking out loud why something which has been on the market for such a long time only recently has seen such a crazy amount of innovation.