Craig Hockenberry makes some excellent points about the possibilities and pitfalls of using multi-touch technology on a desktop computer:
The iPhone’s multi-touch UI works similarly: if you watch people use it, I think you’ll see a lot more people working at waist level than at chest level. The only time you need the interface close to your head is when you’re enjoying those 3 pt fonts in MobileSafari :-)
He’s not the first person to point out that no-one will want to spend hours reaching up to touch a notebook computer’s screen, but his reminder is useful nonetheless. If multi-touch is indeed coming to our computers, it will have to come via a different route.
There are delicious avenues for exploration, though. Bigger, wider touchpads. Or perhaps, using iPhones and future iPods as wireless touchpads, complete with interactive display elements that marry up with on-screen controls. Or just giving into geek demand and creating a Mac tablet - think iPhone, but stretched until the screen’s about 13 inches big.