Facebook crunched some numbers and played Mythbusters on the “Six Degrees of Separation” law:
Calculating degrees of separation in a network with hundreds of billions of edges is a monumental task, because the number of people reached grows very quickly with the degree of separation.
Imagine a person with 100 friends. If each of his friends also has 100 friends, then the number of friends-of-friends will be 10,000. If each of those friends-of-friends also has 100 friends then the number of friends-of-friends-of-friends will be 1,000,000. Some of those friends may overlap, so we need to filter down to the unique connections. We’re only two hops away and the number is already big. In reality this number grows even faster since most people on Facebook have more than 100 friends. We also need to do this computation 1.6 billion times; that is, for every person on Facebook.
I’m 3.55 degrees of separation from anyone else in the world thanks to Mark Zuckerberg’s monolithic social network.
(Via Matthew Cassinelli)