Stephen Penn

“A group can be defined by an attribute (for example, women, Democrats, lawyers, long-distance runners) or as a specific collection of individuals to whom we can literally point (“those people, right over there, waiting to get into the concert”). A social network is altogether different. While a network, like a group, is a collection of people, it includes something more: a specific set of connections between people in the group. These ties, and the particular pattern of these ties, are often more important than the individual people themselves. They allow groups to do things that a disconnected collection of individuals cannot. The ties explain why the whole is greater than the sum of its parts. And the specific pattern of the ties is crucial to understanding how networks function.”
― Nicholas A. Christakis, Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives

“Because of our tendency to want what others want, and because of our inclination to see the choices of others as an efficient way to understand the world, our social networks can magnify what starts as an essentially random variation.”
― Nicholas A. Christakis, Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives