Some technological revolutions arrive as revelation. You hear a human voice wafting out from a rotating plastic disk or see a moving train projected onto a screen, and you sense instantly that the world has changed. For many of us, our first encounter with the World Wide Web a decade ago was one of those transformative experiences: You clicked on a word on the screen, and instantly you were transported to some other page that was served up from a computer located somewhere else, across the planet perhaps. After you followed that first hyperlink, you knew the universe of information would never be the same.