I was reading a Smashing Magazine article about iconography and how the use if it is so important wen you are trying to get a user to do an activity on a screen that’s small. It showed how popover menus to tell you what an icon means is a fail. Users will not remember what it was before when they hovered and most people don’t hover on their phones! So all those fancy mouse over tips, lost to the mobile user. Also most mobile users prefer to use their thumbs and mapping showed how uncomfortable it was to navigate using the top bar on your phone. So yet another fail, we should be putting our navigation at the bottom!