• by Erik Sass , Staff Writer @eriksass1, July 21, 2014

Terrorism is already scary enough without throwing the word “swarms” in there, but that’s what European intelligence officials are warning may already be happening thanks to social media, which enables spontaneous, decentralized terrorist movements to arise and carry out attacks without the need for a traditional hierarchical organization.

Last week the head of Dutch intelligence, Rob Bertholee, told CBS News that terrorists are moving away to from top-down organizations with “vertical communication,” like Al Qaeda, to a new system of leaderless decision-making via “horizontal communication” by the collective “swarm,” using social media.

Bertholee’s description closely resembles the behavior of actual swarming insects like bees: “So what we see now is what you could call a group dynamics, swarming, or the idea of swarming, where many individuals, without a visible leader, actually lead themselves and decide on themselves which way they go. You know they all fly in a swarm, there's no leader there. There's nobody who says yeah we have a map and we have to go this way. But amazingly they all go the same way. That is what we see.”

One big advantage of the swarm structure, for terrorists, is that it makes it much harder for opponents to disable the group by knocking out a few key leaders, resulting in a much more durable and flexible organization that can withstand major losses and keep on attacking.

By the same token it’s also worth noting that the Islamic State of Iraq and al-Sham, currently the world’s most prominent terrorist group, appears to have a traditional hierarchical organization, as demonstrated by the emergence of its self-proclaimed “caliph” earlier this month (you can’t get much more traditional than a form of government which last flourished in the 12th century).

Previously I wrote about the role of social media in recruiting aspiring jihadists from Europe to fight in Syria. According to Gilles de Kerchove, the European Union’s counter-terrorism coordinator, social media plays a “huge role” in recruiting aspiring jihadists from Europe to fight in Syria: “A lot of these young jihadists are narcissists. They want to be portrayed with a Kalashnikov, they put themselves, their pictures, on YouTube, Facebook. They try to encourage colleagues, friends to join.”

Previously, de Kerchove estimated that around 2,000 people had traveled from Europe to Syria to participate in the civil war, where many get mixed up with Islamist extremist groups. Over one-third of that total came from France, he said, while around 270 came from Germany, according to German interior minister Thomas de Maiziere.