Player Distances is a bukkit plugin that measures the distances between players and writes this to a csv file in the plugin's folder, this is just an experiment so that you can see some data about how spread out your players are, you can then compare this to the average for all servers here:
If you think of a new feature please file a ticket.
The source code is available in the jar file
This plugin utilizes Hidendra's plugin metrics system, which means that the following information is collected and sent to mcstats.org:
There is only one command. /savedistances - This saves the total distances to the plugins folder in csv format.