Do you subscribe to the "it's a small world out there" philosophy? If so, you recognize that even though there are billions of people in the world, the chance that you share some sort of odd connection with any random stranger out there is at least reasonable.
Everyone's heard of the "Six Degrees of Separation," or maybe its more pop-culture oriented cousin Six Degrees of Kevin Bacon. Both of those theories state that any two humans on the planet are separated by only a few jumps. For instance, I could somehow connect myself to some random girl in Siberia through six degrees, or six people between us. This would result in about seven jumps, or connections.
Or, as my Uncle likes to tell during the holidays, his friend's cousin's kid takes a karate class with a guy who worked on Goodfellas with Robert de Niro.
Apparently, things are a little different when you look at the Facebook community. The Facebook Data Team has an interesting post about the connections that Facebook's 721 million+ active users have across the network.
First off, the study found that Facebook's 721 million+ active users have over 69 billion friendships represented. The average amount of friends that any given person has on the site is 190.
Using an algorithm developed at the Laboratory for Web Algorithmics of the Università degli Studi di Milano, it was determined that folks on Facebook are closer to one another than the "six degrees" of common thought:
We found that six degrees actually overstates the number of links between typical pairs of users: While 99.6% of all pairs of users are connected by paths with 5 degrees (6 hops), 92% are connected by only four degrees (5 hops). And as Facebook has grown over the years, representing an ever larger fraction of the global population, it has become steadily more connected. The average distance in 2008 was 5.28 hops, while now it is 4.74.
So it's highly possible that you can pick any random person on Facebook and there would only be 4 people between you guys.
And if that person is in the same country as you, there's probably an even smaller degree of separation - 3 people (4 jumps).
It's a small world of social media, after all.