Facebook is a social networking site that allows you to connect with friends and stay in touch withe each other over time.
Reading Material and Classroom Ideas on Facebook in education:
http://www.edutopia.org/social-media-education-examples-facebook
http://www.facebook.com/education
http://www.emergingedtech.com/2011/03/facebook-in-the-classroom-seriously/
With Facebook, College students can connect with professor and other students in order to keep up with class work and etc.