http://www.asylum.com/2008/08/04/six-degrees-of-separation-theory-holds-true-on-the-web/

From the page: “A study of instant messaging habits supports the concept of “six degrees of separation,” having found only 6.6 steps between any two people.

The number was determined by researchers analyzing the addresses of the 30 billion instant messages sent through the Microsoft network in June 2006 — roughly half of all instant messages delivered worldwide during that time period.”