I've been on Facebook for awhile now and am having a grand time. I've reconnected with a friend from 15 years ago, stayed in touch with a friend from middle school (or junior high, if you prefer), and I enjoy using it to keep in touch with friends, both local and out-of-state; it's great fun!
I recently came across some interesting articles regarding Facebook --
Stanford is offering classes for parents to learn how to use Facebook
Ten signs you're addicted to Facebook
Are you Facebooking?