I use facebook quite a bit, but I stay out of the drama. Well, I had one ex friend starting drama, but I simply blocked her, problem solved.
I love it for networking in the horse world. I bought my last horse because I saw his old owner post on facebook that they were selling him, I hadn't seen him listed elsewhere. I keep in contact with mini friends from all over the country through the "message" system. I know its easy to say to just call them, but we're talking drastic time zone differences, or friends who work different shifts and such, making impossible to catch them on the phone. The messages make me able to "talk" to them and catch up, and they answer when its convenient for them. Plus, it doesn't use the minutes on my phone. I often come to LB for horse advice, but I have also post on facebook. When Moe was sick I got a ton of messages and comments, all of which were very helpful. His old owners Pura Vida Ranch also helped me network to get more advice. I know that there are a TON more "mini and pony" people who use facebook than on lil beginnings, and I like to congratulate them on national wins, etc.
I also run a weekly child playgroup, and we have a private facebook page. Once a parent is in the playgroup, I add them to the page. This allows "open discussion" among the parents, but I prefer it over a parenting web forum, because I have met all of these people in person, and know they arent really some perverted child pedophiles pretending to be parents.
I have reconnected with both my family, and my husbands family. I hadn't seen these members of my family since my grandfather passed away when I was about 5 years old, so it was really neat to find them on facebook. We all set up a family reunion, which has become an annual event. The last time we had seen them, email was unheard of, and over the years people moved, changed their numbers, etc. and everyone lost touch. I had a girl message me the other day that I didn't personally know, but it turned out to be my husbands cousin, he hasn't seen her since he was 10 or 11 years old. Another story of lost touch of everyone, but came across them on facebook. We have quite a bit of family from Sicily, all of whom speak italian, but very little english, if any. My dad speaks italian, as well as my grandfather (both are from Sicily), but no one else in my family does. The only way we communicate with the family in Sicily is by messaging them back and forth, then putting the messages into an online translator to have it translated to english.