Someone once created me a simple plugin like this and i lost it, it was a while ago, but basically a plugin where if a player joins it has + MagicRecon or leave - MagicRecon like this http://gyazo.com/dd8095bb5fd807bf2a68f9ee605f91c6 thanks.
MagicRecon https://www.dropbox.com/s/gj89nr5od3o6drs/JoinLeaveMessage.jar That plugin lets you edit the join / leave messages, color codes supported