1. Did you click any WoW related link be it on e-mail, forums or any hyperlinked pages including your Instant Messenger.
2. Did you download any mods/add-on from any sites on the day or a few day before this event occur.
3. Did any "Blizzard" like e-mail arrive at one of your mail boxes asking for any account related statement.
4. DO you previously log in to your WoW account (be it in-game, Battle.net or forum) in a Cyber Cafe or any foreign places that you rarely or never been to?
5. Does your WoW account password share the same password with all the other program that you are using. be it paypal, e-mail, forums, steam or other related program.

Higher probability that your account have been hacked, your item have been compromised. do mail back to Blizzard and wait for reply. Hoping you could get your item back.

i heard that they will bundle authenticator along with cataclysm box, but expect the box going a bit higher than your usual expansion pack.

slowpoke?