the fact, that society is a very densely connected network in which we are nods, and links represent our numerous social, professional, or family relationships. The most important revelation about networks- the one that is exciting scientists from all disciplines-has little to do with small worlds. Rather it is the realization that networks appearing in all different segments of nature and society are indistinguishable. We now understand that real networks are far from being a bunch of nodes randomly linked to each other. Instead, a few hubs, nodes with an exceptionally large number of connections, keep most networks together. A few individuals with an extraordinary ability make friends keep society together.