Cataclysm added many new flight paths to the world, but Blizzard did not increase the size of the map to select your destination. At times, this makes it difficult to click on where you want to go. To help alleviate that problem, this addon scales up the size of the window 50%, and then decreases the size of each destination button. While this isn't a perfect solution, it can help a lot until Blizzard gets around to doing something about it themselves.
Thanks to everyone in this thread on the official WoW forums reporting this issue to Blizzard!