If you complained about RealID to the ESRB, you might have had your address exposed in this way. I'd strongly recommending various safeguards, including changing your email on battle.net if you used the same email address. Be extra vigilant about incoming emails from unknown sources, scan your system diligently, and if at all possible, switch addresses. I guarantee those thousand email addresses are already on the radar of every gold seller, hacker, and phisher in the WoWiverse.
