Jakob Nielsen, in his most recent Alertbox newsletter:
A big downside for WP7 is that we now observe accidental activation of the system buttons, in addition to the problems of accidental touches inside the apps that plagues iOS and Android.
The best option, as I see it, is to turn home into a toggle. Currently, the stock home button does nothing on the home screen itself (although I have mine set up to load the app drawer). What if it loaded the last app? An easy undo for grazers, and a quick toggle back and forth for people who have fancy widgets they want to check.
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