ISIS and other international terrorist organizations rely on the Internet to disseminate their extremist rhetoric and to recruit people to their cause, particularly through popular online social media applications. Any meaningful counterterrorism strategy must, therefore, account for the ways in which terrorist organizations use the Internet to prey on young, manipulable minds who are drawn to radical ideas and propaganda and to the desire to serve a cause larger than themselves. This article outlines the ways in which extremist organizations use the Internet to ensnare new recruits, analyzes the implications of cyber-recruitment on existing counterterrorism techniques, and suggests ways in which the U.S. government can work with Internet service providers and other major cyber corporations to better address this growing threat.