There's Fishing Season, Duck Season, Rabbit Season, and the like; but if there's one thing I've learned during my time on the internet, it's that we are always in "Hacking Season."
Indeed, Battle.net has been breached, with the hacker(s) making off with a list of email addresses "for players on North American servers (which generally includes players from North America, Latin America, Australia, New Zealand, and Southeast Asia)," as well as "the answer to the personal security question, and information relating to Mobile and Dial-In Authenticators."
The company claims that while credit card information has not been accessed, users' "cryptographically scrambled," account passwords have been acquired. Said passwords are reportedly protected with Secure Remote Password Protocol, "which is designed to make it extremely difficult to extract the actual password, and also means that each password would have to be deciphered individually."
In the meantime, Blizzard states that it has been in contact with law enforcement, to determine the origin of the latest incident. While the company claims that users' passwords are safely encrypted, users who use the same password for multiple accounts (such as Facebook, Gmail, etc.) are encouraged to change those as well. As a closing thought, Battle.net posted the following:
In the coming days, we'll be prompting players on North American servers to change their secret questions and answers through an automated process. Additionally, we'll prompt mobile authenticator users to update their authenticator software. As a reminder, phishing emails will ask you for password or login information. Blizzard Entertainment emails will never ask for your password. We deeply regret the inconvenience to all of you and understand you may have questions. Please find additional information here.
We take the security of your personal information very seriously, and we are truly sorry that this has happened.