Using a Vector-Autoregressive (VAR) model, this paper analyzes the relationship between Islamist terrorist attacks and Internet searches for the phrases such as “join Jihad” or “join ISIS.” It was found that Internet searches for “join Jihad” and “taghut” (Arabic word meaning “to rebel”) preceded the Islamist terrorist attacks by three weeks over the period January 2014 to December 2016. Internet searches for “kufar” (the derogatory Arabic word for non-Muslims) preceded the attacks that resulted in deaths from the Islamist terrorist groups. Casualties, including those injured and killed by the Islamist groups, were also found to precede Internet searches for “join Jihad” and “ISIS websites.” Countermeasures to the usage of social media for terrorist activity are also discussed. As an example, if Internet searches for specific terms can be identified that precede a terrorist attack, authorities can be on alert to possibly stop an impending attack. Chat rooms and online discussion groups can also be used to disseminate information to argue against terrorist propaganda that is being released.