A BattleTag is a unified, player-chosen nickname that will identify you across all of Battle.net – in Blizzard Entertainment games, on our websites, and in our community forums. Similar to Real ID, BattleTags will give players on Battle.net a new way to find and chat with friends they've met in-game, form friendships, form groups, and stay connected across multiple Blizzard Entertainment games. BattleTags will also provide a new option for displaying public profiles.[...] You can use any name you wish, as long as it adheres to the BattleTag Naming Policy.I am glad they have seen the light. There are all sorts of problems with giving away a real [sic] name within a game.
From a technical perspective, the tradeoffs they choose for the BattleTag names are interesting and strike me as solid:
If my BattleTag isn't unique, what makes me uniquely identifiable? How will I know I'm adding the right friend to my friends list? Each BattleTag is automatically assigned a 4-digit BattleTag code, which combines with your chosen name to create a unique identifier (e.g. AwesomeGnome#3592).I'll go out on a limb and assume that the user interfaces that use this facility will indicate when you are talking to someone on your friends list. In that case, the system will be much like a pet names system, just with every name including a reasonable default nickname. When working within such UIs, they will achieve all of Zooko's Triangle. When working outside it, the security aspect will be weaker, because attackers can make phony accounts with a victim's nickname but a different numeric code. That's probably not important in practice, so long as all major activities happen within a good UI such as one within one of Blizzard's video games.
Regarding pseudonymity, I have to agree with the commenters on the above post. Why not do it this way to begin with and not bother with RealID? They can still support real [sic] names for people who want them, simply by putting a star next to the names of people whose online handle matches their credit card. Going forward, now that they've done this right, why not simply scrap RealID? It looks like high-level political face cover. You have to read closely in the announcement even to realize what they are talking about.