It's the concept of social networks as we understand it that is outdated.
Facebook and Myspace before it where nothing more than personal PR firms where an individual could whitewash the dirt out of their life in order to present a dishonest version of who they are and what they are doing.
People can never be truly "social" in this environment. In fact they can't even be real people.
"Social Networking" will die. It will go back to what it was before the failed attempt to force us all into an online "I.D. Card".
People will have their steam friends, where they share their love of gaming, their skype lists for collaboration with professional contemporary's, and what ever else in the realm of interest focused social tools might pop up.
This is the most important point. "Interest focus". There is no need for people who share common interest to whitewash their lives (or even mention it unless they feel inclined). It is something facebook and every other attempted social network has completely failed at.
I fear that in some way, facebook has been bleeding into reality. That somehow people have begun living the cleaned and marketed lives they created for themselves on facebook, and in some way we have begun to loose a very important truth about relationships.
You cannot love, or even like someone unless you can love their faults.