Given the number of people who don't have or don't use Facebook, I think there are a lot of people who don't derive social value from social networking.
seems to me people who use facebook a lot do it bec it's a status thing: they have to be in on the latest trend, they have to be in on the latest tech. just the same with people who just have to have the latest gadgets... it's all very superficial
or a lot of people using other social networks. Or a lot of people that don't know they "need" social networks. Or a lot of people that can't use social networks (eg grammas and grandpas, 12-year-olds, people in countries where FB is blocked...)