A new analysis of Twitter accounts that support ISIS provides one of the most comprehensive looks yet at the militant group’s online success in spreading its message.

The paper, The ISIS Twitter Census, was released Thursday by the Brookings Institution’s Center for Middle East Policy, having been commissioned by Google Ideas. It’s a deep dive into how sympathizers of the Islamic State of Iraq and Greater Syria use the platform to disseminate graphic multimedia of its crimes and push out propaganda while simultaneously drawing in support.

The report’s two authors conservatively estimate that 46,000 to 70,000 Twitter accounts were used by ISIS supporters from September to December 2014, though not all of them were active at the same time. “Typical” supporters were located within Iraq and Syria, where ISIS militants control large swaths of land, and accounts averaged about 1,000 followers each. About one-fifth of supporters made English the primary language when their accounts were registered, and three-fourths opted for Arabic.

MORE: Inside ISIS: A TIME Special Report

Specific areas that were studied included display names, top hashtags and links, avatars and smartphones used to send tweets (Android handily tops Apple). “Much of ISIS’s social media success can be attributed to a relatively small group of hyperactive users, numbering between 500 and 2,000 accounts, which tweet in concentrated bursts of high volume,” the report notes.

Its release comes on the heels of ISIS apparently threatening Twitter co-founder Jack Dorsey after at least 1,000 accounts of supporters were taken offline in recent months.

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

Read the full report at Brookings.

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