Perhaps the last generation to embrace Facebook as their social network might be Millennials. Business Insider interviewed a section of Generation Z - the 9 to 11 year olds. Here you can view the video.
Essentially the pre-teens framed Facebook as their grandparents' or parents' social network. The way they communicate is through Instagram, et al. There is also their fear of hackers who they perceive hover around Facebook and will steal their photos.
Since advertisers want youthful demographics, eventually Facebook could hit a revenue wall. Generation Z is the largest generation ever in America. Also, members of it are very different than are the typicals among Millennials. So, whatever social networks marketers leverage to reach them, the pitch will have to be different. For example, they are authentically altruistic.
Here is an article I published on Generation Z for Payment Week.