In an attempt to further integrate its entire fan community into the Battle.net service, Blizzard today introduced BattleTags. BattleTags are an official name for a player account so that players don’t have to post under multiple names across multiple games. The BattleTag will be used to identify the player on Blizzard services like forums.
They are an elective service so players who choose to continue posting under their character names will continue to be able to do so. Some have suggested that this may be Blizzard’s compromise with fans who were worried about the RealID system.
BattleTags will also not conflict with RealID, allowing players to keep only their real friends on RealID, and continue to allow others to know them only by an online handle.
BattleTags will not be unique to each player, multiple accounts can use the same tag. However, each account will have an identifier number on their profile so you can distinguish.
Via WoW Insider.