Realm is the World or server where you will level up your character.
Realm is the World or server where you will level up your character. Even though interaction between characters from different Worlds is possible, for a greater immersion in the atmosphere of the game it is better to choose the most densely populated ones. For the Horde EU players they are: Draenor, Kazzak, Twisting Nether. For the Horde US players they are: Area 52, Illidan, Thrall. For the Alliance EU players they are:  Silvermoon, Ravencrest, Antonidas. For the Alliance US players they are:  Stormrage, Sargeras, Proudmoore. If someone you know is already playing the WoW or you are just going to start a journey with someone you know, then choose the same server.