How prevalent is Facebook use among your students and faculty? Are librarians at your library on Facebook?
I would say that at ITP the numbers of students, staff and faculty on Facebook are fairly small and still reflect the the field's tendency to be less tech-oriented. But I think it is growing. Especially as there are collaborative projects and groups that promote a sense of community that is not geographically dependent.
I wasn't an early adopter on Facebook but joined last year. A few friends found me and I found them. The lovely thing that happened was that many students and faculty at ITP found me! It is proof positive that we are part of their sphere and it was a nice feeling.
There is still the dance between privacy and social connection. I haven't had problems with students or faculty because of this connection. I consider my work fairly public and so I am not so concerned with people knowing who I am and where I work. Not having a secret life, I consider it an extension of my work to go where my patrons are.