The Islamic State in Iraq and ash-Sham (Isis) has taken control of huge swathes of Iraq and Syria, as well as hundreds of millions of US dollars.
Already notorious for their brutal and fanatical extremism, it might come as a surprise that they're also highly adept at using social media.
The group has been deploying an astute strategy across Facebook and Twitter, using it to spread its message to the wider public, build up its populist credibility and help indoctrinate sympathisers. Its online campaign is highly sophisticated and effective.
It has established both a top-down and bottom-up communication network with a global audience, which has even left counter-terror practitioners and government officials many steps behind. There are a handful of central Isis actors who tweet and update pro-Isis Facebook pages to fully spread the news of their victories. Leading Isis Twitter accounts also provide constant updates and commentary on the situation on the ground.
Some of these accounts have upwards of 20,000 followers each, with the most prolific online activists streaming their feeds to over 35,000 followers.
Others predominantly release images and footage of captured weaponry and equipment, while still others tend to post horrific images of their victims.
The group also uses social media to expose the failures of the Syrian and Iraqi governments, and debunk their narratives on the crIsis. In a sense, uploaded photographs are used to mark territory. Hundreds, if not thousands, of photos have recently emerged showing Isis' control of civilian and military airports, border crossings with Syria, banks and television stations.
This is an effective form of propaganda on its own, but also challenges the Iraqi government's statements about the success of its counter-attacks.
Foreign fighters and grassroots supporters are also setting up profiles and accounts to share their experiences, retweeting information in an effort to help recruit new supporters and members.
The day-to-day concerns of the group are also discussed online, including issues as menial as whether or not there is access to the Internet in certain locations, what the availability of women is like, and how hot it is.
While many accounts are in Arabic, there are a good number that are written in fluent English and other languages.
What this proves is that social media is allowing dangerous communication between militant groups to occur in real-time, and with little consideration for border controls, censorship or rank. So what is to be done?
As discussed in a recent Quilliam report, negative measures (such as blocking, censoring or filtering extremist accounts) do little to remedy the problem, often attacking the symptom rather than the cause. Instead, the information on sites like Twitter should be used as a key source of intelligence-gathering.
The Isis social media campaign has taught governments a harsh lesson that misleading propaganda, particularly that which exaggerates false victories, is easily debunked.
Because of this, governments should always be transparent and clear when explaining their policy decisions.
Groups and individuals concerned by the rise of groups like Isis must also use their presence online to help channel a counter narrative on social media.
Instead of just watching everything unravel online, they should call terrorist groups out on their crimes and attack their inhumane beliefs.