Using records from the Microsoft Messenger Instant Messaging database, researchers have just proven (again) the Six Degrees of Kevin Bacon theory:
With records of 30 billion electronic conversations among 180 million people from around the world, researchers have concluded that any two people on average are distanced by just 6.6 degrees of separation, meaning that they could be linked by a string of seven or fewer acquaintances.
The database covered all of the Microsoft Messenger instant-messaging network in June 2006, or roughly half the world's instant-messaging traffic at that time, researchers said.
"To me, it was pretty shocking. What we're seeing suggests there may be a social connectivity constant for humanity," said Eric Horvitz, a Microsoft researcher who conducted the study with colleague Jure Leskovec. "People have had this suspicion that we are really close. But we are showing on a very large scale that this idea goes beyond folklore."
Link - Thanks Geekazoid!