Blizzard Authenticator Introduced
From the official WoW site:
To help players avoid unauthorized account access, we're introducing the Blizzard Authenticator, a keychain token that generates codes that must be entered when signing in to the linked World of Warcraft account. For full details, please check out the official announcement or visit the information page.The Authenticator will be available from the Blizzard store for $6.50 and will be available at, and after, the WWI event, and is completely optional.