Originally Posted by Blizzard Entertainment
Naming
Names are subject to the same rules established above. Any name the player has the ability to customize—such as player names, BattleTags, and guild names—must be appropriate and inoffensive. Any name that violates our standards or disrupts the community will be changed, and additional limitations may be placed on the offending account per our discretion.
Take note that acceptable names are determined by player reports and Blizzard's decision, and role-playing servers may have distinct standards for using game-appropriate names.