I think a significant portion of the issue is just that people have started to see and experience the downsides of projecting a running tab of their life for al

I think a significant portion of the issue is just that people have started to see and experience the downsides of projecting a running tab of their life for all to see, for all time. As people become more technologically literate, the appeal of selling your personal info for the dubious privelage of nothing much has to pale. I imagine the revelations that governments (US especially) are warehousing every scrap of data they can find on us hurts too. Mostly though, FB is boring and depressing, and eventually even the easily swayed figure that out.