Gold farmer: Okay joe! Powerlevel done! Enjoy gold and ninja'd epix!
(3 months later...)
Joe Schmoe: What the fuck? Someone logged on my account and stole EVERYTHING in my bank, including my 10,000 gold pieces and epic blow up doll collection!
Typical scenario, and no, I don't make this shit up. Although, the stolen items & currency are usually refunded, it's just asking for trouble if you sign up for something like this. Don't give your password(s) out to complete strangers, and you'll be better off for it.