In schools, a lot of the discussion about social networking focuses on how students are using (or misusing) popular sites like Facebook or MySpace. But social-networking sites can be incredibly useful for teachers, too. Need an idea for how to teach the popular young adult novel The Book Thief? Curious about how Second Life can enhance classroom learning? The answers to all these questions can be found online. But social-networking sites aren’t just about linking people to resources. They’re about linking people to people—and fostering critical discussion.