Here's an object. We interact with it. All through the mouse (or your weapon of choice). I've been involved in hundreds of web sites and their interaction design.

The most common convention for feedback is the rollover. We've all made an on and off graphic and hacked abit of javascript to do the image replacement.

Crank up the tech and get flash involved. OK, more interesting animation and interaction happening but still control by single input.

Then the iPhone came along with its touch interface. How exciting for user experience gurus and creatives alike. Not really, the input method is largely the same except now our trusted rollover feedback mechanism is dead - a tap is a click.

I've been involved in concepting the experience for a number of iPad projects. Get the thinking right, do the design, whack it in a perspective graphic of an iPad and bingo, looks almost real to touch.

So what's the big deal then? Fingers, that's what.