The Apple iPhone's success hinges on one thing..
by phil on Saturday Jan 13, 2007 9:09 PM
thinking about design
.. the distance between the surface of the phone and the pixels that represent the GUI. The key in any user interface is the melding between human body and machine. The primary concern, and this has been reiterated elsewhere, is that you touch the iPhone, but it doesn't touch you back. There's no tactile feedback. And that's a serious, potentially fatal issue. I had a heat-sensitive touch-pad keyboard, and I eventually ditched it because you'd only hit keys correctly 99.5% of the time. That seems like a successful hit ratio, but it's that .5% that messes everything up. It made me have to look at the keyboard too much. It interrupted my flow of typing. Ultimately, it reduced my wpm on a Dvorak layout to the same speed as QWERTY.
Not all touch-screens are bad. The Nintendo DS is a fair example. It uses a pen mostly, which gives you good precision. Plus, the screen is so small that there isn't much deviation between where you touch and what the device registers. While as on my tablet PC, a couple of milimeters of deviation between the pen and the input creates a system that is a complete failure. I think this is because the screen is too thick, and so even with slight changes in viewing angle, you never can get the tip of your pen to line up right with the cursor. Even when you try to run the calibration programs where they ask you to touch various corners of the screen, it can never feel as precise as pencil and paper. And so you just ditch it and resort back to the keyboard and mouse.