The Islamic State in Iraq and the Levant (ISIL) continues to control a significant part of northwestern Iraq, including the country's second largest city, Mosul. They dominate much of the eastern half of Syria and are engaged in ongoing battles in both countries. They are behind the recent attacks in Kuwait, Tunisia, andEgypt.

However, ISIL's reach extends beyond the territories they control or the places they strike. Through a sophisticated social media network, this armed group is spreading fear by publicising its gruesome crimes, disseminating information about its achievements around the world, raising funds, and reportedly recruiting close to 1,000 new members a month.

With high-quality videos posted to YouTube, smartphone apps, online chatrooms, and Twitter/Facebook accounts sending messages in multiple languages, ISIL has become very good at using new tools in waging their information war.

At least 46,000 Twitter accounts were actively promoting the work and ideology of ISIL between September and December 2014, according to a new study from the Brookings Institution.

The US State Department has repeatedly said that "countermessaging" is essential to defeating ISIL. But President Obama's administration has acknowledged the armed group is far better at spreading its message than the United States is at countering it.

So why is it so hard to defeat ISIL in the information war? We discuss at 19:30 GMT.