Side note: the physical Home button that brought the device into a well-defined state was a godsend for new users. I observed this with both my parents and my grandparents: whenever they got "lost" somewhere, the fact that they could always press that button (and don't have to look for it! it's always in the same place, it's not auto-hide etc) and get to a familiar place, made things a lot easier. Oftentimes they'd use it in lieu of other, faster ways of getting from here to there - but I figured it's more important that they can get there.