Someone tried to steal my WoW account in a new way today. Some level 62 toon I'd never heard of whispered me out of the blue "could I have your account name? I'm making a collage. Don't worry I can't steal your account because I don't have your password". Needless to say that's a pretty weak request, there's no legitimate reason for anyone to ever know your Blizzard account name. Don't give it out.
The same day, a friend of mine got spam whispered by a toon named "wotlkbeta" inviting them to go to a website to sign up for the beta. Another ridiculous request, but one I'm sure naive people fall victim to.
There are sustained, coordinated attacks against Warcraft accounts. Stripping a typical level 70 toon nets at least $50 worth of gold. And unlike credit card fraud, there's no particular penalty or enforcement against WoW thieves. It's serious illegal business, another organized crime racket on the Internet. This is why you should never buy gold; you're funding the thieves who are stealing your friends' accounts.