This paper examines the concept of cyberterrorism. Fringe activity on the Internet ranges from non-violent 'Use' at one end to 'Cyberterrorism' at the other. Rejecting the idea that cyberterrorism is widespread, the focus here is on terrorist groups' 'use' of the Internet, in particular the content of their Web sites, and their 'misuse' of the medium, as in hacking wars, for example. Terrorist groups' use of the Internet for the purpose of inter-group communication is also surveyed, partly because of its importance for the inter-networked forms of organisation apparently being adopted by these groups, but also due to the part played by the Internet in the events of September 11 and their aftermath.