The idea of homegrown terrorism is not a new concept, especially considering the history of challenges faced by the United States and other Western countries. However, the current violent jihadist problem has overshadowed those past misfortunes in terms of its objective and volatility. What is emergent is the means by which the individuals involved in this movement reinforce or possibly operationalize their radicalized behavior. The Internet is often that vehicle. Efforts to reform U.S. intelligence have placed increasing value on open-source information for threat assessments. Consequently, the open Internet has been targeted in search of radical actors, both foreign and homegrown. Some analysts contend that the availability of radical discourse on the Internet presents an opportunity for early identification by authorities. This thesis analyzes the value of open-source exploitation of the Internet in the domestic counterterrorism role in relation to other detection techniques in order to extract best practices and lessons learned for improved intelligence and law enforcement activities.