I have a Facebook account, rarely post anything on it, my Internet "home" is Tumblr.
It can be depressing, indeed, but what Facebook is showing me is nothing I didn't know already, it just provides more tangible insight into the lives of these people I know, like former school/high school colleagues. Most of them have good jobs, some moved to another country(which was one of my biggest dreams growing up and still is), have relationships. Sometimes it does bother me because I have none of that but with or without Facebook, I would have still been aware of them doing those stuff.