Valve says it's Steam service hasn't been hacked. Earlier this week a hacker claimed to have broken into the service and obtained credit card information from Steam users:
Doug Lombardi, director of marketing at Valve, says, "There has been no security breach of Steam." However, he does confirm our expert's findings by adding, "The alleged hacker gained access to a third-party site that Valve uses to manage the commercial partners in its Cyber Café program. This Cyber Café billing system is not connected to Steam. We are working with law enforcement agencies on this matter, and encourage anyone with more information to e-mail us at Catch_A_Thief@valvesoftware.com."