OCCUPATION: Perceptive Pixel founder
PREVIOUS APPEARANCES ON THE TIME 100: 1
PRO: It's been only two years since Han introduced Multi-Touch, a technology that allows users to manipulate digital screens using multiple fingers; now it's everywhere, from your iPhone to CNN's election-season "magic wall."
CON: When CNN correspondents get too tap-happy, the results can be dizzying. Would it kill John King to use an overhead projector?