Small-world Networks

In the book "Nexus: Small Worlds and the Groundbreaking Theory of Networks" we return to Stanley Milgrams experiment of sending out letters to random people, asking them to return the letter to a specific person somewhere, under the restriction of sending to personal relations only. This led to the notion of six degrees of separation, that everybody in the world is connected to everybody else in on average six friend of friend-steps.

Later research has shed some additional light on the social structure of human societies. The distribution of the number of relationships people participate in would intuitively follow a bell-curved distribution, as it happens for height and IQ measures. The numbers tell a different story. It follows a power law: A few persons have an enormous social base, while many have a few relations. How is this different from, say, height? In practice, many people might be 1.7 m tall, a few might reach 2.1 m. If height followed a power law we wouldn't be surprised if, now and then, we met some people measuring 4 m or in rarer cases 100 m.

Could this be an argument in favor of viral marketing? Instead of spending resources on mass media, some companies could identify the hubs of our social fabric and start a dialogue.

This kind of marketing has already been raised as an ethical-political issue in Denmark, as some companies have given away brand name clothing to primary school pupils perceived to be associated with high social status.