During the Cold War, US intelligence struggled to penetrate the Kremlin, which ran the Soviet Union with an iron hand. Today's intelligence professionals say terrorist groups like al Qaeda pose an even more difficult challenge. True believers won't take bribes and scoff at threats of retaliation. So US military and intelligence agencies want to update another Cold War strategy: deterrence, using the Internet to sow confusion, dissent and distrust. Can language skills and cultural understanding separate moderate Muslims from the extremists? Are western policies the real problem? Is al Qaeda better at high-tech propaganda than the US and its allies?