Terrain marker

A Terrain marker is an object used to mark a location on the terrain. Generally, it is placed by using an item to spawn the object, but could be placed by a spell or an ability.

Any placeable object can mark terrain, but in order to be useful the marking object must be:
 * Visible over a distance - in WoW, that generally means a large object
 * If subtlety is warranted, a small object may server better
 * Persistent - no fixed duration, but generally at least tens of seconds or several minutes
 * Stays in a fixed location - if it wanders, it can't mark a spot on the map

Varieties

 * Smoke Flares are the quintessential example. The Smoke Flare pyrotechnic device places a smoke column on the terrain.
 * White Smoke Flare
 * Green Smoke Flare
 * Purple Smoke Flare
 * Red Smoke Flare
 * Cannoneer's Smoke Flare (blue, Horde quest item)


 * Lunar Festival terrain markers. These two stones create a column of light on the terrain.
 * Elder's Moonstone
 * Elune Stone


 * Ad Hoc, generally smaller objects. Anything that can be placed; examples:
 * A campfire, placed by using the Basic Campfire skill.
 * A keg of Brewfest Brew, placed by using a Brewfest Pony Keg (not consumed) - if you have the item, the use is free
 * Summoning a Snowman companion (requires and consumes a Snowball)
 * A Portal, summoned by a mage. It doesn't matter where the portal goes, it is being used for its graphic property in the game environment (requires and consumes a Rune of Portals (original))

Uses
Some uses that people have come up with:
 * marking locations for raids
 * smoke bomb the Flag Rooms in the Warsong Gulch battleground
 * props for floor shows and fashion shows