No, the reason the 26-year-old CEO matters is because he's not just entertaining those people: he's building them their own, self-contained World Wide Web. There's now so much to do within Facebook that its fans need never leave. They can play games, read news stories, browse pop stars' fan pages, even do some shopping using Facebook credits. This year, Facebook has launched Places, a mobile application that lets you share your location using on your phone; Questions, which lets your friends and friends of friends answer your queries; and Messages, an inbox combining messages from within Facebook with emails, text messages and instant messages from outside. Essentially, Facebook could replace your email.