I do use FB a lot...but it used to be primarily a network of college students, 20-somethings and maybe some 30-somethings. Now my 70+-year-old grandfather even has a FB! My mother will call me, not to ask how I'm doing or check on the kids...but to ask me what I was talking about in my status update from earlier in the day. It's cracking me up to watch so many people who were computer-illiterate 10 years ago now be addicted to Facebook.
I like Twitter so far...