This software obtains the information directly from Blizzard, the company that develops World of Warcraft. It is capable of offering information about the type of server as well as the amount of people that are currently using it. The information is shown graphically by means of colors, something that makes the data easier to understand. All this information can be accessed from the menu bar at the top of the screen. You will only have to press on the corresponding option to see all the servers and their status.
If you are a hardcore World of Warcraft player and you want to have more control about the servers that you use to enjoy this great game, you have to download WoW Status.