03/06/2015 02:34 EST | Updated 05/06/2015 05:59 EDT

ISIS supporters on Twitter come from small group, study says

The battle against ISIS on social media is finding some success, but the extremist group is also finding ways to adapt, according to a new study on how ISIS exploits Twitter to spread its message.

A first-of-its-kind census, done by the Brookings Project on U.S. Relations with the Islamic World, catalogues ISIS’s use of Twitter and estimates there are at least 46,000 Twitter accounts linked to ISIS supporters. While the number could be as high as 90,000, the study found most of group’s social media activity comes from a dedicated group of less than four per cent of those users.

It found those users to be highly effective at getting their message out, even as Twitter attempts to crack down on ISIS-related accounts.

"They employ a variety of techniques, including repeated tweets of the same content by the same user within a short period of time, and tweeting the same content by many users within a short period of time," the study finds.

Other findings include:

- No overt ISIS supporter has more than 50,000 followers.

- ISIS-supporting accounts average 1,000 followers.

- One in 5 ISIS supporters select English as primary language.

- Top locations for accounts: "Islamic State," Syria, Iraq, Saudi Arabia

- 69 per cent use Android, 30 per cent iPhone, one per cent BlackBerry

The report comes out less than a week after Twitter employees received death threats from ISIS over account suspensions. Recent reports estimate the social media company blocked 20,000 accounts linked to the militant group in February alone.

"Account suspensions do have concrete effects in limiting the reach and scope of ISIS activities on social media," the report says. "They do not, at the current level of implementation, eliminate those activities, and cannot be expected to do this."

The study also found that while suspending accounts creates obstacles to supporters trying to join ISIS’s social networks, it found the process can also isolate ISIS supporters, forcing them to abandon moderate accounts in search of hard-core radicals, which could speed up radicalization for those who do find a way to get in.

The study paints a picture of typical ISIS supporters, who are generally found in Syria and Iraq and areas where ISIS is fighting to gain territory. It also found that hundreds of accounts sent tweets with the location data enabled.

The study’s authors acknowledged that account deletions as well as ISIS users' habit of changing names, deleting accounts, holding private accounts and multiple accounts by the same user, made it difficult to get accurate numbers.

Twitter, which didn’t participate in the study or provide internal data, isn’t commenting, but a spokesman said, "We review all reported content against our rules, which prohibit unlawful use and direct specific threats of violence against others."