Basis: A small and clustered world

From Barabasi’s Small World:

Clustering in society is something we understand intuitively. Humans have an inborn desire to form cliques and clusters that offer familiarity, safety, and intimacy. However, a property of the social network is only of interest to scientists if it reveals something generic about most networks in nature. Therefore, Watts and Strogatz’s most important discovery is that clustering does not stop at the boundary of social networks.
Thanks to the high interest in clustering generated by Watts and Strogatz’s unexpected discovery, the scientific community has subsequently scrutinized many networks. We now know that clustering is present on the Web; we have spotted it in the physical lines that connect computers on the Internet; economists have detected it in the network describing how companies are linked by joint ownership etc.
The discovery that clustering is ubiquitous has rapidly elevated it from a unique feature of society to a generic poperty of complex networks and posed the first serious challenge to the view that real networks are fundamentally random.