A new study by Princeton University researchers, called "Epidemiological modeling of online social network dynamics," uses diseases to model the life and death of social media networks. In it, the researchers conclude that Facebook will lose 80 percent of its users sometime between 2015 and 2017--signaling a warning sign for businesses too attached to any single social network.

http://www.inc.com/lydia-belanger/why-facebook-is-like-a-disease-and-what-you-should-do-about-it.html