For two hours yesterday, the website of American Express was unavailable. The company had become the latest victim in a long series of cyber attacks on the United States, likely carried out by the Izz ad-Din al-Qassam Cyber Fighters, a group that may have strong ties to the Iranian government. The history of these recent attacks is detailed by The New York Times, but the report suggests that such groups' success and cyber power shouldn't be the primary cause for our concern. "We don't know how they make decisions," security expert James A. Lewis told The New York Times. "When you add erratic decision making, then you really have something to worry about."