The internet has emerged as an important medium for terrorists. Two key trends can be discerned from cyberterrorism: the democratization of communications driven by user generated content on the internet, and modern terrorists’ growing awareness of the internet’s potential for their purposes. The internet has become a favorite tool of the terrorists because of the many advantages it provides, such as easy access; little or no regulation, censorship, or other forms of government control; potentially huge audiences spread throughout the world; anonymity of communication; fast flow of information; interactivity; inexpensive development and maintenance of a Web presence; a multimedia environment; and the ability to influence coverage in the traditional mass media. These advantages make the network of computer-mediated communication ideal for terrorists-as-communicators. Terrorist groups of all sizes maintain their own websites to spread propaganda, raise funds and launder money, recruit and train members, communicate and conspire, plan and launch attacks. They also rely on e-mail, chatrooms, e-groups, forums, virtual message boards, and resources like YouTube, Facebook, and Google Earth. Fighting online terrorism raises the issue of countermeasures and their cost. The virtual war between terrorists and counterterrorism forces and agencies is certainly a vital, dynamic, and ferocious one. It is imperative that we become better informed about the uses to which terrorists put the internet and better able to monitor their activities. Second, we must defend our societies better against terrorism without undermining the very qualities and values that make our societies worth defending.