Two years ago this happened to me.

I know how it happened, I opened an email that was not from blizzard and they put a trojan on my computer. I had to wipe it completely to get rid of the virus. It was a key logger trojan that not only took my wow information, but all my banking information too, which they waited on for about three months then started going to town on that. It was quite a mess for awhile.

They hacked my four wow accounts, took all the gold off of 28 toons, sold all their gear and left them all naked. I was at least thankful they didn't delete any of the characters.

Blizzard was amazing, but slow. They were very helpful and sympathetic and their research took about one month of total time, but I got ALL my gear back and ALL the gold I had at the time, which wasn't much. It was helpful that I knew the exact hour the hackers struck, because I logged off. Tried to log in an hour later and all my passwords had been changed.

Since then I have an authenticator and only access WoW on my playing computer. I changed all my wow accounts over to a wow-only email account (and b-net).

I didn't want to lose my orignal email account because I've had it for over 20 years, so since the time of the hack, I get tells every day to my main toons from chinese farmers trying to sell gold and at least 15-20 emails a day from "blizzard". I just report them all as spam and never open them.

One thing Blizzard needs to do is what EQ2 has done. Allow you to turn off tells/whispers and all chat from anyone of certain level groups. In EQ2 I turned off everyone under level 20, so that I never got the spam in cities from gold sellers and the numerous level 1 toons they made over and over couldn't /whisper me any of their spam either.