Originally Posted by NatCh
That's more or less correct -- it's an electronic field effect of some sort, not simple magnetism.
For a time I was very much hoping that it would be something directly manipulable by a simple magnet, since that would have suggested a lot of possibilities in the area of input. But, alas, 'twas not to be.
I can follow your trail of thought; a simple pen with a magnetic pin could make it like a magnetic drawingboard (like found in kids toystores).
However it would make it hard for the device to read that input, so the magnetic input would be limited on the screen, and can not be saved into the memory.
Maybe an idea for future developements?