I like being able to nosey at see what family and friends are up to. I find it most useful for keeping in touch with people you don't see regularly, but who are still on the Christmas card list and in your thoughts now and again, such as ex-colleagues, and friends who live in faraway exotic places like Swindon
I have 60 FB friends, which is small potatoes compared to most. One friend of mine, who has travelled the world and taught in various countries, has over 1800, which might explain why I am forever being asked whether I know an endless parade of Japanese people. Easy to ignore. A couple of my friends are very keen on posting daily inspirational messages that make me want to reach for the sick bag, so I hide their messages, and just "visit" them occasionally to see what they're up to. My OH thinks FB is the work of the devil, but isn't above asking me to pass on messages to our mutual friends 