ISIS Threatens Facebook And Twitter Founders Mark Zuckerberg And Jack Dorsey
The threat was part of a 25-minute video created by ISIS and posted to Telegram, a social media messaging app with a claimed 100 million monthly active users. It was discovered and viewed by Vocativ, which reports that the video contained pictures of Zuckerberg and Dorsey strewn with bullet holes.
"You announce daily that you suspend many of our accounts, and to you we say: Is that all you can do? You are not in our league,” ISIS states in its video clip. "If you close one account we will take 10 in return and soon your names will be erased after we delete your sites, Allah willing, and will know that we say is true."
The account closures on Twitter and Facebook have pushed ISIS members to seek out alternatives, like Telegram. Just a few weeks ago, Twitter announced that it suspended over 125,000 accounts for threatening or promoting terrorist acts, adding that they were primarily related to ISIS. Facebook has also been active in shutting down accounts belonging to terrorists, though it hasn't disclosed exactly how many.

ISIS relies heavily on social media to spread its propaganda and to recruit new members. The effort to stifle the organization's efforts seem to be paying off—a study (PDF) from George Washington University found that Twitter's suspensions are having a "very significant detrimental effect" on repeat offenders.