Prior to the iPhone, most touch-sensitive devices used resistive touchscreens. These rely on two or more conductive films sandwiched together that respond to finger or stylus pressure--and the amount of pressure required is the issue. Resistive screens simply aren't that sensitive--usually not enough for fingers, or gestures, at least. Cheap touch phones still use them.

Ever keen to eradicate unnecessary buttons and keys, Apple used a capacitive screen for the iPhone, whereby the screen is covered in a conductive material. Finger pressure doesn't matter, and styluses don't work on capacitive screens because they rely on the fact human that skin is conductive.

Thus, Apple proved it was possible to articulately operate a cell phone using your fingertips. They even introduced gestures, such as pinching your fingers together to zoom into or out of photographs.

3. Jailbreaking

Pundits have spent millions of words pondering why . Many users hate the evil symbiosis. Along with the fact it took the iPhone a while to launch overseas, shortly after its release hackers set out to crack the tight controls Apple put in place to limit the iPhone to just one vendor.