Upon logging into the game for the first time and trying to use any of the following features:
* Mail
* Auction House (accessing, buying, selling, anything)
* Whisper
* Trading with players
You may be presented with an error message: "This feature is currently disabled/unavailable for your account".
This error message relates to the activation of your account and the confirmation of your valid email address. When you sign up for a new account, you are asked for your email address. After registration is complete, the system will send you an email asking you to confirm it. If you do not confirm your email address this way, when you login to the game you will not be able to use any of the above features.
If you did not receive such an email, or maybe even perhaps have mis-typed your email, please contact support.