Classes of hundreds pose special challenges for teaching and learning. Notable among these challenges is the tendency for students to feel like anonymous spectators rather than active, collaborative participants. To combat this tendency, we used the popular social networking site Facebook to cultivate a sense of community among 200-plus students in an Introduction to Sociology course. The Facebook Group proved a powerful tool for community-building and learning. We describe our Facebook Group, present evidence of its benefits in the course, and discuss the pedagogical potential of social media.