Jerry lost half a digit and replaced it with a prosthetic finger with a USB drive inside. He explained on his blog that it's detachable: "When I'm using the USB, I just leave my finger inside the slot and pick it up after I'm ready."ATLANTA, Georgia (CNN) - In Chris Harrison's ideal world, mobile phones would be the size of matchbooks. They'd have full-size keyboards. They'd browse the Web. They'd play videos. And, most importantly, you'd never have to touch them. Sound like too much to ask? Maybe not. Harrison, a graduate student at Carnegie Mellon University and a former intern at Microsoft Research, has developed a working prototype of a system called Skinput that does just that, essentially by turning a person's hand and forearm into a keyboard and screen. "People don't love the iPhone keyboard. They use them. But they don't love them," Harrison said in a interview at the recent Computer-Human Interaction conference. "If you could make the iPhone keyboard as big as an arm -- that would be huge." Using Skinput, a person could tap their thumb and middle finger together to answer a call; touch their forearm to go to the next track on a music player; or flick the center of their palm to select a menu item. More