The Third "N"

Node C: better to be at the center to pick up gossip.
Node D: better to be at the periphery if
there's a virus going around (YAM photo)

Yale professor Nicholas Christakis believes that social networks are a very old phenomenon:

the basic structure of social networks has been with us as long as we have been human. Moreover, it hasn’t changed much despite the invention of agriculture, cities, and telecommunications. “If you talked with your great-grandmother” who had no phone or “my teenage daughter who has a phone in her pocket,” he says, they’d both have the same small circle averaging 4.5 close friends.

According to Professor Christakis the difference is that now we have the technology to analyze networks [bold added]:

first, cell phones, Twitter feeds, medical administrative records, and countless other sources now make possible “massive, passive” gathering of data about social networks. New computational methods also allow researchers to identify social patterns in this sea of data and begin to make sense of them. And finally, inexpensive and widely available DNA sequencing technologies provide a window into the genetic character of these networks.

To be sure, some of this science just gives a name to what people already know ("homophily - the same inclination of similar people to form ties together"; "degree assortativity - the knack of popular people for befriending other popular people"). The work has produced enough results, however, that it's a safe bet a third "n", networks, will soon be given equal weight as nurture and nature in determining how an individual's life turns out.