Signpost

Signposts were a new feature added to the game around May 1, 2006.

Signposts are a slightly more permanent form of carving messages into a location. Once you have 2 pieces of driftwood in your inventory, a button appears that allows you to construct a signpost. The signpost appears as a small icon on the jungle map, and the text of the sign can be read once you enter the square. Signs cannot be defaced or vandalized, but they can be destroyed by a determined attacker.

(Driftwood can be found on the beaches, and is also often available in trading posts.)