As you fly N-W-S-E in the outlands, eventually you will hit an invisible wall. Also, if you are off the map so far and you dismount for any length of time and get too low, you're character will begin to fall without the camera chasing you and you die.
When you hit one of these invisible walls as a druid, making sure you're up high enough not to loose control of the character, shift out for about 3 seconds, and shift back in. You will be able to pass through the invisible boundary and continue flying in the direction you were headed.
You won't see much, you're screen will tend to go fairly white, and once you get so far (to the map limitation) you will DC from the server, upon relogin you will be at the boundary. Attempting to fly any further will continuously DC you. I haven't found anything useful for this but its worth noting what happens when you die as it's quite stupid.
If you are at the limitations of the map, and let yourself die now, you will spawn in the barrens for horde, and west fall for alliance. These are the default spawn locations when a character dies in a place where the server does not know where to put them, basically a safe catch to prevent a game breaking bug for a player in which they can't play.