The Facebook Dilemma

So, I finally jumped on the Facebook bandwagon. My roommate, who is a GSI for an undergrad economics course at UMich, was telling me about how her students sometimes request to add her as a friend and she adds them but feels kind of awkward about it. At least she's dealing with college students. However, as secondary teachers, I wonder if it's appropriate to label our students as "friends" in this context. I'd love to get comments on this...