Islamic State sympathizers using social media to spread propaganda and recruit fighters are drawing an increasing amount of return fire from activists who have been knocking some sites offline and infiltrating others.
The loose hacking collective Anonymous is the latest to draw attention to such campaigns, with members claiming credit this week for having thousands of pro-IS Twitter accounts disabled.
But others claim to have been doing more for longer. One group that feeds information to the U.S. government says it has suppressed tens of thousands of Twitter accounts since January, and its members have posed as would-be recruits to gain information on so-called dark Web operations supporting the Islamic State.