ISIS has an army of at least 46,000 Twitter users

The Islamic State, the violent extremist group that espouses a return to a seventh-century caliphate, has been astonishingly successful at spreading its message using 21st-century social media, according to a study released Thursday. Despite repeated attempts by Twitter to thwart the Islamic State’s threats, propaganda and recruiting by suspending accounts linked to the group, sympathizers have maintained thousands of active accounts on the social network, the study said. The users include a disciplined core group that sends messages frequently and understands how to maximize its impact. “Jihadists will exploit any kind of technology that will work to their advantage,” said J. M. Berger, an expert on online extremism who was the lead author of the study, which was published by the Brookings Institution and financed by Google Ideas. But the Islamic State, he said, “is much more successful than other groups.”