Twitter is targeting the so-called Islamic State (IS).
IS and its supporters are facing "significant pressure" due to an increase in Twitter account suspensions, according to terrorism expert J.M. Berger, author of a forthcoming book on the militant group.
Berger, who spoke this week before the House Committee on Foreign Affairs, said that "the most active and viral users [are] taking the brunt of the suspensions" and that supporters of IS have called the suspensions "devastating."
His testimony was based on an upcoming paper investigating IS’s use of Twitter slated to be published in March.
Twitter, Berger said, initially "took an extremely permissive approach to the question of what content it would permit," in contrast to Facebook and YouTube, which allowed users to flag content that supports terrorism.
Twitter did not respond to a request from VOA for information on the number of suspended accounts.
But Berger said that the beheading of American journalist James Foley seemed to prompt Twitter into taking a "more aggressive approach" to IS, suspending "thousands" of accounts.
The research documented some 45,000 Twitter accounts used by IS supporters in the fall of 2014.
Berger said he documented 800 account suspensions of confirmed IS supporters, plus another 18,000 suspensions among whom many were likely IS supporters. He added that there would likely be "a lot more" than 800 when the report is finished.
Berger added that 73 percent of IS supporters have fewer than 500 followers and that none they found had more than 50,000. In contrast, he said, in early 2014 some IS supporters had more than 80,000 followers.
Vulnerable to suspension
Highly active accounts were most vulnerable to suspension, Berger said.
"Suspended users tweeted three times as often as those who were not suspended, and received almost 10 times as many retweets from other ISIS supporters," he said. "Suspended users averaged twice as many followers as those who were not suspended."
Berger said there are three benefits from the “current level of [account] suspensions."
First, he said, it reduces IS’s "reach among online populations at risk of radicalization."
Second, "by allowing some ISIS accounts to continue with a lower profile, the current level of suspension activity preserves a substantial amount of open-source intelligence," he said.
Third, "targeting the most active members of the ISIS supporter network undercuts IS’s most important strategic advantage on platforms like Twitter -- the 1,000 to 3,000 accounts that are, at any given time, far more active than ordinary Twitter users," Berger added.
John Horgan, the director of the Center for Terrorism and Security Studies at the University of Massachusetts Lowell, said Bergen’s research is something policymakers should follow closely.
"Extremists have had free reign on Twitter, and they exploit it to the fullest," Horgan wrote in an email to VOA. "[Bergen] demonstrated just how much the suspensions hurt IS supporters, as well as how it impacts IS’s overall social media strategy."
'They always come back'
But Pieter Van Ostaeyen, a Belgian blogger and freelance terrorist tracker, was less impressed with the effects account suspensions are having.
"I know fanboys and fighters who have been suspended as many as 16 times, but they always come back," Van Ostaeyen wrote in an email to VOA. "I tweeted last year [that] IS supporters on social media are like mushrooms in a moist meadow -- you pluck one, only for four to replace it."
Van Ostaeyen said the English-language accounts are more often suspended and the Arabic ones are "hardly ever deactivated."
"ISIS propaganda has been available as usual," he wrote. "It's not that hard when you're following the right accounts. Some of these guys act as hubs, if one user is suspended it's through former following accounts they build up their network again."
Jytte Klausen, a Brandeis University professor and founder of the Western Jihadism Project, which focuses on jihadi activities in the West, is conducting similar research. She said she can’t be sure of the effect of account suspensions.
"We are witnessing increased decentralization to a large number of far smaller ‘relay’ accounts," she wrote in an email to VOA. "It is not clear to me, however, that the Islamic State and the recruiters have been seriously inconvenienced by the increase in take-downs."
'A realistic goal'
Berger maintains the suspensions are having an effect.
"No reasonable person is arguing for the complete eradication of IS supporters from Twitter," he wrote in an email to VOA. "That is not a realistic goal. A realistic goal is to limit the ability of IS to use social media to do whatever it wants, whenever it wants. And that is what is happening here."
Twitter is not alone in its concern for terror postings.
Google said Wednesday that its video-sharing website YouTube is flooded with terror-related content and that staff cannot filter terror-related content fast enough.
"That’s complicating the struggle to halt the publication of terrorist propaganda and hostage videos," Reuters reported.