Here is a video I created to make a case for 4 reasons Facebook is valuable in the classroom: http://www.youtube.com/watch?v=tUN0cv28pgs

In short, it:

(a) creates a bond between teacher and student that is beneficial to the classroom environment

(b) encourages students to actively produce content rather than simply absorb like sponges

(c) its community-based format fosters discussion, reflection, social awareness, and what Stanley Fish termed the "interpretive community" effect

(d) makes students sensitive to different dialects/formalities of English