The University of Arizona Artificial Intelligence Lab Dark Web project: “Based on our actual spidering experience over the past 5 years, we believe there are about 50,000 sites of extremist and terrorist content as of 2007, including: web sites, forums, blogs, social networking sites, video sites, and virtual world sites (e.g., Second Life). The largest increase in 2006-2007 is in various new Web 2.0 sites (forums, videos, blogs, virtual world, etc.) in different languages (i.e., for home-grown groups, particularly in Europe). We have found significant terrorism content in more than 15 languages…We believe our Dark Web collection is the largest open-source extremist and terrorist collection in the academic world.”