I, for one, like Facebook for the fact by joining groups I've been able to help quite a few people with their tanks. At least, I hope I have anyway, lol. Granted, its not as personable as a forum and people get mad over the stupidest things. I always recommend them joining a local forum though.
Things like FaceBook and Twitter are an important part of advertising now. I've caught myself looking at websites to see if they happen to use either. Guess its, to me anyway, proof of said company is serious. If they take the time to create and update those feeds it shows they're real about what they do.