Valve is the latest in a string of companies to have their information accessed by outside means. On Sunday, November 6, the Steam's forums were attacked, which lead to an in-depth search by investigators. They concluded that a database containing personal informal such as user names and passwords was accessed. Valve founder Gabe Newell released a statement regarding the attack. While there is no evidence of credit card number violations. it is probably wise that everyone with a Steam account go ahead and change their password. I, for one, even changed the associated email address.
I am truly sorry this happened, and I apologize for the inconvenience.
Stay tuned for more information as it develops.