Irwin,
Yes, Facebook is quite different from the other outlets mentioned here and I agree, a separate account for school and work should be set up when using this social media tool. When studying sociology for example, Facebook is a gold mine; it is knowing when and if it is appropriate that is key. LinkedIn on the other hand is a fantastic tool for all students and future graduates and has the potential to increase placement rates as well as your institutions visibility in the field.
Wishing you continued success in the classroom.
Theresa Schmitt