Oracle of Baseball (http://www.baseball-reference.com/oracle/) uses a database of every MLB player to track how “connected” different players are to each other. It attempts to link two different players using common teammates. For example, I could type in Cy Young and C.C. Sabathia (the 2007 AL Cy Young Award winner) and I will be shown the fewest number of steps to connect them. This example results in 7 steps, which seems like a lot at first…until you realize that Young retired in 1911 and died over a half century ago. This shows not only how connected the current baseball landscape is, but also how closely linked baseball is to its heritage.
Certain players that played for many teams (such as Rickey Henderson) or played for many years (like Julio Franco) serve as common links between many players. However, the Oracle allows you to eliminate certain players to find other paths. Therefore, a three step link through Henderson may have another route around him, possibly requiring more steps. This shows that local bridges are almost always not the sole way to link different parts of the network.
This site is a fun database to play with, and the results are not surprising to anyone familiar with the small world phenomenon.
In case you wondered, it’s 6 links from Alex Rodriguez (2007 HR leader) to Jim O’Rourke (1880 HR leader)