In Chapter 1 of my 2002 book Living Networks I wrote:
When did you last say or hear someone say “what a small world”? People have an unquenchable fascination with how richly we are connected, never ceasing to be amazed by the seeming coincidences of how one friend knows another through a completely different route. Yes, it is a small world, and growing smaller all the time. The well-known phrase “six degrees of separation” suggests that we are connected to every person on the planet by no more than six steps.
After explaining the concept, its origin, and how ‘small world theory’ is helping us to understand the nature of social networks, I continued:
From six degrees, we are moving closer to four degrees of separation from anyone on in the world, with the possible exception of a few isolated tribespeople. We live embedded in an intensely connected world.
That prediction is being borne out today. A paper just submitted to arXiv titled Four Degrees of Separation, says that a study of the entire network of 721 million Facebook users with 69 billion relationship links shows an average distance of 4.74 degrees of separation.
![4degreeschart](https://rossdawson.com/wp-content/uploads/2011/11/4degreeschart.jpg)
Source: Four Degrees of Separation. Note: it = Italy; se = Sweden; itse = combination of Italy and Sweden; us = USA; fb = all Facebook.
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