First there was the six degrees of separation (the notion that if a person is one step away from each person he or she knows and two steps away from each person who is known by one of the people he or she knows, then everyone is an average of six "steps" away from each person on Earth). Then came six degrees of Kevin Bacon (the idea that you can link any actor to Kevin Bacon on average about six steps).
Now, we have the six degrees of wikipedia. This site lets you find the average link between one page and another. Kind of interesting and fun. For example, you only need two clicks to get from Utah State University to Brigham Young University, and only one from the U to the Y (see guys, we don't need a rivalry, we're closer than we think).
I was going to run some more comparisons, but the server is down (probably due to the slashdot/digg effect).
Perhaps the most interesting thing is that by using this analysis, you can determining the center of wikipedia. The author of the article figured out the shortest path on average to a single article, and found that central article to be the United Kingdom. United States was third. What ranked before the good ol US of A?
That's right, you guessed it. Billy Jean King.
No, I'm not kidding. Go figure.