https://www.wired.com/story/new-zealand-shooting-video-social-media/

At least 49 people were murdered Friday at two mosques in Christchurch, New Zealand, in an attack that followed a grim playbook for terrorism in the social media era. The shooter apparently seeded warnings on Twitter and 8chan before livestreaming the rampage on Facebook for 17 gut-wrenching minutes. Almost immediately, people copied and reposted versions of the video across the internet, including on Reddit, Twitter, and YouTube. News organizations as well started airing some of the footage as they reported on the destruction that took place.

By the time Silicon Valley executives woke up Friday morning, tech giants’ algorithms and international content moderating armies were already scrambling to contain the damage—and not very successfully. Many hours after the shooting began, various versions of the video were readily searchable on YouTube using basic keywords, like the shooter’s name.