On the Web, the best way to solve a problem is to engage an extensive network; the person who provides information, advice, or answers is often someone you know only vaguely — a weak link. In the face-to-face world, though, Waber says, groups are more productive when the team members know each other well, sharing extremely strong links. That's because face-to-face teamwork requires intimacy, he says, and "when you're among friends you can really capitalize on preexisting protocols" — nods, grunts, in-jokes — for talking and listening. - Meryn Stol