Somali al Qaeda affiliate al-Shabab woke up one January morning to discover that its popular English-language Twitter account -- @HSMPress -- had been suspended, apparently because it had issued a direct, specific threat of violence in breach of Twitter's terms of service.
This rare termination dusted off one of the counterterrorism industry's most-cobwebbed and least-resolved debates: Should we let terrorist groups use the Internet, or should we try to knock them offline?
When the debate first started, not long after 9/11, terrorist use of social media -- anything from message boards to Facebook accounts -- was concentrated in a relative few channels. Today, it's spread to hundreds of different outlets, including multiple dedicated Web forums, blogs, Facebook, Twitter, YouTube, and beyond.
Stopping terrorists from spreading their propaganda online (using U.S.-based Internet companies to boot) seems like a no-brainer to many. But within the terrorism studies community, there are two common and sincere objections to disruptive approaches for countering violent extremism online.
The first objection is that knocking terrorists offline "doesn't work," because when you eliminate one account, the terrorists just open up a new account under a different name -- which is exactly what al-Shabab did after a little more than a week. And then, the theory goes, you're back to square one. It's a high-tech game of whack-a-mole.
The second objection is that forcing terrorists off the Internet destroys a valuable source of intelligence, because government, academic, and private sector researchers rely on these online operations for information about what distant groups are doing and who supports them. "The intelligence community took the position that you cannot take this stuff, you cannot take these sites, down," intelligence historian Matthew Aid told Voice of America last year after a number of jihadist forums went offline. The argument was that more information was gained "by monitoring these sites than any possible advantage that could be derived from shutting them down. And the intelligence community prevailed on this point."
Until now, there has been precious little data in the public domain to clearly support or refute either notion. But al-Shabab's termination is what scientists call a "found experiment" -- a free lunch in which the universe hands you the data you need to test a theory.
Al-Shabab is a particularly useful example, since its Twitter account has by most measures been one of the most successful terrorist forays into popular social media. But it's not the only one. Jabhat al-Nusra already has more Twitter followers than al-Shabab ever did, and jihadis are by no means the only extremists using the medium. So the lessons learned from this example are likely to have broad applications.
Theory One: Disruption accomplishes nothing because they just come roaring back
I collected a list of @HSMPress's followers on January 16, less than a week before the account was suspended on January 25. At the time, al-Shabab had nearly 21,000 followers. As of Sunday, February 17, two weeks after its creation, the new account had just passed the 2,400-follower mark. (I won't help them out by linking the new account, but it's not hard to find if you're interested.)
Obviously, al-Shabab will continue to rebuild its follower network, but a disruption doesn't have to be permanent to be effective. From January 26 to February 17, al-Shabab averaged about 1,300 followers per day. It currently has less than 12 percent of its former reach. And its followers are in no hurry to come back.
If it maintains its current rate of growth, al-Shabab will need six months to a year to rebuild its former network. While that pace could well accelerate, there's also no guarantee the account will ever fully recover.
Significantly, Al Jazeera English did a story on al-Shabab's return during the period used to make this forecast. The story linked directly to al-Shabab's account, yet it barely moved the needle in terms of generating new followers for the Somali terrorists.