Ghost Wards, placed by the Sightstone and Ruby Sightstone, are functionally identical to Stealth Wards, but are colored white instead of green. The difference is only visible while using the classic ward skins.
Both Sightstone items share the same counter for the number of active wards.
If you place a ward after you already have three out, the first one you placed is removed and a new ward is placed in the position indicated.
Wards grant 30 gold when destroyed (including Ghost Wards from the sightstone items). If the player who reveals the ward and the killer of the ward are different players, the gold will be split 50/50 so each gains 15 gold.
The ward from Wriggle's Lantern grants 20 gold. If the player who reveals the ward and the killer of the ward are different players, the gold will be split 50/50 so each gains 10 gold.
Intelligent usage of wards goes a long way, namely in key brush locations, like intersections, in front of Dragon and Baron Nashor. This is useful for map awareness of potential ganks, champion movements, and/or attempts to kill an Epic Monster. The lone shrub in front of both Epic Monsters is an excellent place to both reveal the river and keep tabs over their presence.
Wards that are placed on a Noxious Trap will cause the mushroom to explode, a damage free method of removing them.
Certain characters with attack-timer refreshing abilities can clear wards in the moments after they are placed.
Using Teleport on a ward will no longer reveal the ward through Fog of War to enemies. Instead, it will destealth the ward to be seen if an enemy is near and reveal the teleport particle through Fog of War to all enemies.