Note that it's from Diablo3 for World of Warcraft.
It has come to our attention that you are trying to sell your personal World of Warcraft account(s). As you may not be aware of, this conflicts with the EULA and Terms of Agreement. If this proves to be true, your account can and will be disabled. It will be ongoing for further investigation by Blizzard Entertainment's employees. If you wish to not get your account suspended you should immediately verify your account ownership.
You can confirm that you are the original owner of the account to this secure website with:
If you ignore this mail your account can and will be closed permanently. Once we verify your account, we will reply to your e-mail informing you that we have dropped the investigation.
Account Administration Team
World of Warcraft , Blizzard Entertainment 2012
Beware! Even though most people wont fall for this, but some might, so I figure I post this up
EDIT* removed hyperlink