Minimapsync

Minimapsync
Making waypoints available on multiplayer servers.

This mod is not yet finished and also isn't a very complex mod, however it is a quite useful mod, which I firstly programmed for a friend of mine and myself. It allows you to synchronize your waypoints created with either Rei's Minimap or Zan's Minimap with other players on the server you are playing on. (only works if the mod is installed on the server) It also allows you to teleport to your waypoints, which is nothing new for Zan's Minimap, but for Rei's it is. This mod post contains no screenshots or videos, because there is not much to see, the mod just works in the background with only a few messages displayed to the user.

Source : http://www.planetminecraft.com/mod/minimapsync/