Rocket, of the development team behind the Arma II mod DayZ tweeted moments ago that "due to sustained and constant hacking, the central database is being dropped until further notice. You will not be able to connect." Kotaku has emailed Rocket for clarification and additional details.
Update: That didn't last long. All functionality was quickly restored; "Server is back online. Those identified as hackers in last weeks have received permabans. Sorry for the downtime," Tweeted rocket.
Update (Midnight EDT): Rocket clarified what happened in extend remarks to Kotaku. BattlEye Innovations, makers of ArmA II's anti-cheat protection, notified the DayZ admin team that they had permabanned—globally—"some thousands of those who had been previously detected cheating and hacking." The hacking attempts were solely to gain competitive advantage in the game; they were not attacks meant to steal user information or gain any type of administrative control over the game.
"At no time could they get control of the server itself, but they could kill other players, remove their gear, make them dance - all sorts of things," Rocket said. "But they could not, say, install files or anything.
"This is a very difficult time for the project, we have been under a sustained attack on nearly every system, both within game and in DayZ," Rocket added. "Without Bastian's help (makers of BattlEye), I am confident the project would have had to close. This, however, only represents an initial step, we will need to keep working with both BattlEye and Bohemia Interactive to achieve the results that those playing DayZ deserve. We have a long way to go to truly improve security but we're committed to that."