[mbq]

Precisely they used capacitive touch sensor (used on touchpads mostly at the time) instead of resistive standard used on PDAs; in practical terms this was a switch from notebook-like experience (which invites writing and checking small boxes) to magazine-like (smooth, glossy surface inviting sliding pages and large Nokia-like UI plus gestures to remove accuracy/finger-hiding problems). This way, multitouch rather just come in bundle with capacitive technology. BTW this is why I see the whole stuff as a mainly target group revolution -- simply way more people buy magazines than notebooks.