This is part of a series of reviews of websites, platforms, and social media sites. Some are useful for teachers in a SMART classroom (with a teacher-station computer, internet connection, and projector). Others lend themselves more to a lab where each student has her own computer. Hopefully these can help us communicate with our students, present information effectively, and encourage collaboration, feedback, and active participation. See our previous review of Wordpress.
You might be most familiar with Facebook as the distraction that keeps pulling your students' attention away from their work in computer labs or even on their phones. You also might also know Facebook as the distraction that keeps pulling you away from your own work as you're supposed to be grading papers or lesson planning. It has a pretty bad reputation as being a procrastinator's swirling vortex of material, with people going so far as to create apps that block it from computers for specified lengths of time so that they aren't tempted to "like" their friend's latest dinner pic when they're supposed to be writing a term paper.
Setting aside that bad reputation for a moment, though, there are some creative ways to harness the usability and ubiquity of Facebook to be a classroom tool rather than a classroom menace.