There has actually been some real research done on this. In 1967 a sociologist randomly chose individuals in the Midwest and asked them to send a package to a stranger in Massachusetts. They were not given an address, but given the name, occupation, and the approximate location of the individual. They were asked to send the package to someone they thought might know the stranger, or would at least know someone else who might know the stranger.
Guess what!? Each package reached its destination, after being sent to (on average) five to seven people. Amazing.
Then in 2001 a professor at Columbia University devised a similar experiment, using the internet. His experiment was done on a much larger scale! He used 48,000 senders in 160 countries, and 19 "targets." The average number of people the email had to go through? Six.
Here's an example from my own life! Have you seen the video of Susan Boyle (I think nearly everyone who uses the internet has!)? Well - I asked my neighbor Mary (who's from Scotland) if she knows her (I asked her more as a joke than anything else), and she does! Her brothers know her well. So I am only two people away from Susan Boyle!
Which famous person do YOU know - maybe six degrees away?
(Image courtesy of USMagazine)