Breaking News Emails
The online reaction spread quickly as expected after a killer posted video of his attack on two former co-workers in the midst of a live news broadcast.
Yet the social media response after Wednesday's killings, which at first seemed perfectly tailored to the internet's instant-sharing culture, did not go entirely viral.
Shocked Twitter and Facebook users urged others not to click on, retweet or otherwise circulate the recording made by Vester Lee Flanagan that he posted before he died hours later from a self-inflicted gunshot wound.
Reporter Alison Parker and cameraman Adam Ward from WDBJ-TV in Virginia were killed.
Some of the strongest requests for restraint came from those close to the victims.
"Our WDBJ crew was literally ambushed this morning. PLEASE DO NOT share, or post the video," tweeted Brent Watts, the TV station's meteorologist.
That request was retweeted more than 2,000 times in the hours that followed, and the sentiment spread far further.
"Please if you see video of the shooting posted on FB or anywhere, take a stand," tweeted former professional hockey goalie and NHL coach Corey Hirsch. "Do not watch or share."
It was far from the first time masses of users avoided recirculating graphic online video. In recent years most have stayed far away from sharing Islamic State militants' beheading videos.