Alyssa Bereznak writes: When Robin Williams died last August, people around the world rushed online to mourn the loss of the actor. “Oh dear God. The wonderful Robin Williams has gone,” Bette Midler tweeted. “No words,” added a somber Billy Crystal. “Shame. I liked Jumanji,” tweeted one England-based Twitter user. “Good movie. Loved it as a kid,” replied an account with the handle @Mujahid4life.

“Mujahid,” for those unfamiliar, roughly translates to “jihadist warrior.” And this particular handle belonged to a 19-year-old British-born guy by the name of Abdullah, who happened to be both a supporter of the Islamic State and a big Robin Williams fan.

Abdullah’s opinion of the fallen star unleashed a torrent of blog posts, most of which marveled at the fact that a member of an organization that openly beheads its enemies could also have the emotional capacity to mourn a U.S. comedian on Twitter. But however surreal it was to watch Hollywood actors and terrorist sympathizers tangle online, those voyeuristic bloggers missed a larger point. That moment encapsulated a key pillar of the group’s now infamous social media fortress: Spreading extremist ideology doesn’t need to start with religious screeds and beheadings. It starts — as a social media 101 instructor might say — by simply taking part in the conversation. [Continue reading…]