This year's Edge World Question Center is out, posing the query mentioned in the title. My own answer is kind of lukewarm -- the internet did allow me to find my future wife, which certainly changed the way I think about a lot of things, but that's not the tack I wanted to take for this project. Instead, I'm basically giving credit to you blog readers for keeping me honest. (Among other things.) But many of the other answers are fascinating. Just to pick some at semi-random, I enjoyed the responses from Danny Hillis, Anthony Aguirre, Frank Wilczek, Victoria Stodden, Martin Rees, Scott Atran, Lisa Randall, Irene Pepperberg, and Clay Shirky. Keep thinking!