The use of Web sites by terrorist groups has been evident since the mid 1990s. Security experts and researchers have identified terror-related Internet activity as a growing area of concern, especially following the attacks of September 11, 2001. Terrorist groups using the Internet pose two distinct threats. The first is cyberterrorism: terrorists using the Internet destructively and directly to bring about harm to persons or property, including, attacks on Web sites. The second is the use of the Internet as a communication medium to further the cause of terrorism or a particular organization. As of 2008, Weimann (2008b) estimated that over 6,000 terrorist Web sites exist, but the definition of a terrorist Web site is not always clear. This study analyzed the content of 30 "extremist" sites and defined those as sites that endorse hatred and violence towards the United States and its allies by sharing their hatred and actively promoting their ideologies online. This research examined the source of the message, the message content, the types of receivers intended, the channels used to communicate the message, the purpose of the message, and the effects of the message. Results indicate that a major purpose of the organizations is to justify their actions to skeptics. The organizations have built a virtual extremist community with each other and outside members where their sum is greater than their total. The actual impact of these sites is difficult to measure. However, while Web 2.0 features are employed on these sites, this study argues that censorship and forum rules restrict members from engaging in a real dialogue thus limiting the potential of recruiting moderates.