This is ThottBot. I usually go to this page when I need some information about a certain mob, item, skill, race, class, profession, maps, and just about anything that you can ever think of inside the World of Warcraft. This includes everything that you can never get when you are just simply playing and not minding or thinking about things that you see within the game.
It categorizes everything depending on how one would use the specific search item in WoW. And this feature makes it even cooler with additional side comments from the players themselves.