Although networks are still in their infancy, experts think they're already creating new forms of social behavior that blur the distinctions between online and real-world interactions. In fact, today's young generation largely ignores the difference. Most adults see the Web as a supplement to their daily lives. They tap into information, buy books or send flowers, exchange apartments, or link up with others who share passions for dogs, say, or opera. But for the most part, their social lives remain rooted in the traditional phone call and face-to-face interaction.

The MySpace generation, by contrast, lives comfortably in both worlds at once. Increasingly, America's middle- and upper-class youth use social networks as virtual community centers, a place to go and sit for a while (sometimes hours).