Are their limits to social media and humans' capacity to engage meaningfully? Oxford Psychologist Robin Dunbar's recent paper examined if social media use today affects the maximum 'number of stable relationships a human can maintain', known as Dunbar's number (see Jan.23, 2016 issue of The Economist, p. 73 or link below). The Economist reports that in looking at two samplings of Facebook users and working adults, the recent paper by Prof. Dunbar found the average number of their Facebook friends was 187 and 155 respectively -- which aligned well with Dunbar's famed number of 150 maintainable relationships calculated in the 1980s. The original Dunbar research was based on trying to understand primates and their strong focus on grooming (see second link below for excellent prior article in The New Yorker by Maria Konnikova on Dunbar and more of Dunbar's #s: 150, 50, 15, 5, 500 and 1500, each a unique engagement circle).

The Economist: http://www.economist.com/news/science-and-technology/21688846-online-social-networks-do-not-change-fundamentals-friendship-done-bar

http://www.newyorker.com/science/maria-konnikova/social-media-affect-math-dunbar-number-friendships