lookin sweet, but.. wtf is a skybox? O__o
Skyboxes were used back in older games (Lets take one of my favorite games: Star Wars: Jedi Knight 3 Jedi Academy into example).
You would have the objects ingame, your map, bla bla bla, and if you went out into the edge of the map, you would see a pretty low quality (or high quality, depends on the game) background image, and the model would consist of a box, with the background textures. They however would tend to make it impossible to see the textures connect at the edges of the box, else it would look weird.
WarCraft 3 uses Skyboxes, thats why if you do View Ingame Settings, and zoom out alot, you'll see the skybox.
World of WarCraft uses Skyspheres, which is the same thing, except its in a sphere, and looks more realistic.