Night/Day difference explained between Storm1 and Storm2
 

http://www.youtube.com/watch?v=dmlLPtRAbuw

Piezoelectric screens are neither capacitive nor resistive. They operate by the piezoelectric phenomenon of quartz crystals. It's the conversion of mechanical energy into electric (it works the other way around as well, as oscillating crystals, used for creating a clock signal. It behaves like an RLC circuit). To use his sponge analogy, this makes the screen bend where you press it, thus giving you a tactile feedback.