What didja expect? Theres nothing to do in the void. I know for sure it makes for faster travel between the three easter peninsulas of Outlands (Netherstorm, Hellfire, Shadowmoon) if you have a flying mount. :D
I wonder what happens when you go TOO FAR OUT into the blankness?
Zone also shows up if you use an Eye of Killrogg off the side of the world. I tried it in Zangarmarsh, off the west coast. Eventually the graphics will screw up (as in the camera will stay in one spot while the eye falls off the world) and it will say you're in The Twisting Nether.