As a part of our ongoing dedication to account security, players who utilize authenticators on their account will now be asked to enter it upon their first time logging into the forums, and then periodically thereafter. By ensuring that, even if their account is compromised, without the attached authenticator their login credentials can’t be used. This additional security layer helps to better protect players in all services accessed by logging in with their account and password.
We’d like to urge all players who don’t already use one to please consider attaching an authenticator to help protect themselves and their accounts. Information on how to obtain an authenticator as well as additional account security information can be found at: http://www.battle.net/security/