The web has become one of the most powerful tools today used by terrorist networks like the Islamic State, or ISIS. Two researchers — physicist Neil Johnson and computer scientist Hany Farid — are among the many to come out with new technologies aimed at understanding and stopping terrorists using the internet. Farid, with Dartmouth College and the nonpartisan policy group Counter Extremism Project, created a way to make it easier to scrub terrorist propaganda from the web. They join Here & Now's Robin Young to talk about their work.