This is a very simple, and lightweight plugin.
What does it do?
This plugin allows players using the compass, to right click, then track other players.
How does it work?
When a player right clicks holding a compass, the compass will find the closest player in the same world as him, and track it. The compass stops tracking if the player is closer then 30 blocks.
How is it useful?
This compass is very useful for PVP servers, it allows players wanting a fight, to find one, with ease.
This exact same plugin was developed for survival.ownedcraft.com, it's now released on Bukkit after popular demand.
