What is a Battle.net BattleTag?It sounds all very simple, nothing harmful about it.
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.
Now, internally, this was already being used (every user had a unique ID), but Blizzard had no financial use for this information other than internally to Battle.net. They're making it so that their customers can see this unique identifier for themselves now, use it to communicate, and so that they spread the ID around the internet and to other social sites. :)
Right now it's "optional", but they'll eventually make it mandatory for all players.
It has been received very well, players are saying that it's what Real ID should have been, and many are even calling it "Real ID 2.0".
You'll probably notice a very strong connection of this new development to this older post too: "You Are Being Prepared"
This new service, though, is more of a "Real ID 1.5". It's just another stepping stone for player acceptance, and eventually leading to something even bigger that players aren't aware of.
Having one nick name (across Battle.net, games, Blizzard websites, and community forums) is definitely very useful.. for Blizzard friends only. But remember that there's always another purpose. Even though it's not your real name, you've been handed a mandatory unique identifier that's now public facing. :)
Players, will of course, have fun with their new nickname and also start to use it to identify themselves on webpages and forums that are outside Battle.net. Players will use this "unique code" on Facebook, Twitter, and other social networks. Who knows where else this will be shared. (Also, you'll notice in their announcement that Blizzard will be creation optional Public Profiles for users, much like Facebook.)
These are just some of the first steps getting more players integrated with Facebook directly, or more importantly, finding a way to link Battle.net players to external websites and social networks. Don't be surprised if a new application is created for Facebook that displays your Blizzard gaming details using your BattleTag.
And, speaking of Facebook applications, remember that they have full access to everything to type. It doesn't matter what security or privacy settings you have.. if you write a confidential secret message to a friend, Facebook has complete access to it, and their marketing partners (Blizzard) will have access to it.
This BattleTag is useful to some players, but it's even more useful to Blizzard marketing (for the future purposes of targeted advertising) because it acts as a tracking ID: *1-12 max characters* # *4 digits*
Consider how useful that unique identifier is when web crawling or data mining. In Twitter for example, you can search for "@name" to find everything they've posted, who has messaged them, what their Facebook profile site is, what Forums they're on (if they share their Twitter account), if they're on Yelp, if they use those "Check In" services (so that you know where they are, what restaurants they go to), etc.
All of this can be fully automated.
Here's a very simple example too. On the first day of the announcement, several MMO-Champion users already posted their new BattleTags. "buggerlugs#2442" was one of them. There are 60 different players in the US called Buggerlugs and 68 in the EU. Out of 128 players in NA/EU alone, I now know exactly which "Buggerlugs" is the same one who posts on the MMO-Champion forums. Just knowing this alone is scary. But I also know that he's a male, complains about WoW every chance he gets (but can't stop playing), thinks that Blizzard Artists are cheap, I'll know what other games he plays when the service goes fully online, I know that he's very likely from the UK, and he really doesn't like the US (he finds it hilarious to make fun of Americans.)
Now, if he had a FB profile and I had a partnership with Facebook (like Blizzard does), I would also have full access to his profile and every private little message he's ever written (or even deleted). I would know where he lives, other sites he posts on, his family (and how to get his family playing Blizzard games), his likes and dislikes, nearby stores or restaurants, what he wants for Christmas, everything he's said about Blizzard (which he thought was anonymous), etc.
Even without a FB profile (or a partnership), all it takes is one slip up to link together dozens of "anonymous profiles" to one single person. This is what the internet does. So.. really, how is this any better than Real ID?
And all of this was done very smart this time around. Players are very positive towards this new change, they're welcoming it, encouraging others to use it ("BattleTags" sounds awesome), and they'll never be aware of how it will be used eventually to bombard them with suspiciously specific advertisements in the future. :)
I think a lot of this will be very useful for Titan, if they can search for and use this information properly Many companies have tried and failed on this front, and everyone thinks they can do better (things tend to get overcomplicated). There may even be ads on their Blizzard public profiles and remember too that the Blizzard/Facebook partnership goes both ways.. that is, Facebook ads using Blizzard data. Data from either FB or Blizzard can be used by either parties or even by affiliates (in any case, it will always be a win-win situation).