Imma make it simple. A player teleport system
/tele <playername> then the other player will get a request to /tele accept or /tele decline. real useful stuff.
There is already a suggestion for that idea. You can add your votes to that: http://8bitmmo.uservoice.com/forums/150844-general/suggestions/3393456-create-a-where-is-player-name-command-
That is practically a Exact copy from minecraft! And Sim9 already has that ability and he does not want to share it!