Blizzard Debut's New Battle.net System

With the release of the new battle.net, players can enjoy a new "centralized account system" which will allow you to log into World of Warcraft and eventually future battle.net games using only one account. Other features include: keeping track of all your games and Blizzard cd keys under one account, access to the wow armory (and probably similar websites upon future game releases,) management of your Blizz store purchases and also an expected (but not yet developed) communication system between games.
An "evolution" of Blizzard Account's, you'll no longer need multiple logins for all your Blizzard games. You can now merge your different gaming accounts (currently just WoW but to include Starcraft 2 and Diablo 3) to your battle.net account. If you did previously have a Blizzard account it will be converted to a battle.net account.
Visit
http://www.battle.net for more details.