This mod add pings (markers) that last few seconds (this can be changed in config).
Using Ping is incredibly simple. Both the server and client must have it installed. To send a Ping, simply hold down the V key, and select a ping type by either mousing over it and releasing. A Ping will then be sent to everyone in configurable radius or to everyone in your team when you have FTB Library installed. If a Ping is offscreen, a small icon will render on the side of your screen, pointing to it.