Some places in Arda are considered being well suited for keeping watch of the surrounding terrains. These are known as watchtowers, but can be anything between the tower of a castle and a high hill.

If you find one of these watchtowers, you can use the command watch to start keeping watch over the terrain around you. When in 'watch-mode', you get information about players moving about where you can see them.

You can also use search <direction> to scan for people standing still.