Before anyone trade, if you decide to do it, you need to request from "trader" picture and cd key picture, also ID card copy, its not only email and password. In this case, after some time, trader can request password change from support, and to say "I'm Hacked :(" so he will only need to send picture of cd and id card to bnet support, and he have account back. So be aware when you are this, if you dont want to be "scamed"
ps. I am not saying that "xabber is scamer" but just be aware when you are trading with bnet accounts.