From City Journal: You Say Potato, I’ll Say Potato.

Before Facebook, few of us asked others, explicitly, to be our friends. We didn’t monitor how many friends we had as an indication of our status or scroll through listings of friends of friends to pad our own list.

Yet the history of humanity is a history of social networking all the same, according to Nicholas A. Christakis and James H. Fowler, authors of Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives. “Our connections affect every aspect of our daily lives,” they write. “How we feel, what we know, whom we marry, whether we fall ill, how much money we make, and whether we vote all depend on the ties that bind us.” And the burgeoning field of network research is revealing that “our connections do not end with the people we know.” Social networks take on lives of their own, transmitting information, germs, and habits between people who are nearly as tangentially linked as actors in the old parlor game Six Degrees of Kevin Bacon. “Friends of friends of friends can start chain reactions that eventually reach us,” the authors argue, “like waves from distant lands that wash up on our shores.”