"It's like we have this beehive – and then you go and beat on it and the bees go everywhere," says Aaron Y. Zelin, author of the study and a fellow with the Washington Institute for Near East Policy, in an e-mail interview. "It might be a lot easier to keep an eye on those bees and their activities while they're still in the hive."
Concerns that terrorists might embrace social media have been around for several years, but use of the platform has been limited. While Osama bin Laden was alive, terrorists did use social media to a degree for hate speech, recruitment, and training. Still, most Al Qaeda sympathizers remained tethered to Arabic- and English-language websites, which require a login and password to chat, download literature, and view videos and other material.
But those forums are under increasing strain. Al Qaeda's top-tier forum, Shamukh al-Islam, was down from Dec. 5, 2012, to Jan. 29, 2013, according to the study. That takedown, as well as two other major strikes last spring, left a void and accelerated migration to social media, which now is "beyond a point of no return," Mr. Zelin says.
Other researchers have registered similar observations. Evan Kohlmann, an expert on online jihadism, tweeted in December: "Due to the absence of top jihad chat forums, al-Shabab ... in Somalia has been forced to rely on Twitter to distribute its latest video release. This may be the first time that any terrorist group allied with Al-Qaida has ever used Twitter as the exclusive point of release for media."
New technology helps. New features on Twitter, Facebook, and YouTube make it far easier for global "jihadi entrepreneurs" to share articles, news, and videos.
"The newer technologies lowered the bar for participation, making the involvement of low-level or non-jihadis in the online conversation a new feature of the global jihadi movement," the study says. "Those so inclined can talk about jihad all day on the Web, even if they are geographically dispersed. This was not possible beforehand."