I agree with most of the sentiment in the thread.
Social media is such a strange phenomena. I think what you're seeing now is the early signs of individuals revolting against open public forums, accessibility of private information and open channels of communication.
The early luster of gaining such things 8-10 years ago has worn off and folks are realizing they don't want their personal profile out there (on the Internet); they don't like the fact unknown entities/people/companies from across the globe can gain access into their private lives; and they've learned they don't really need to know about the mundane daily routines of some distant contact they haven't spoken to since the 2nd grade.
I'm also intrigued about the sociological affect of social media on this generation. There was a study (I'll try to look it up and source it) that looked at how people live out their "best self" on platforms like Facebook. They post photos of themselves on beaches, at some trendy club, at some event, et cetera, which to an outside viewer makes the person look like they are living a fantastic and eventful life and subsequently makes the viewer feel subconsciously wanting or inadequate and causes them to start posting their "best self."
On a personal level, I'm not active on Facebook anymore for the simple fact that apparently all these people I know were secret politicos, life coaches and uber religious.