Two-Way readers were immediately struck by a sense that the victims of the Aurora, Colo., shooting could have been anyone, as well as shock that something as simple and fun as going to a movie could turn violent without warning:
"As a self-proclaimed nerd, I usually go to movies like this on the opening weekend," says "Miss M," who adds that "I just keep imagining this theater full of people having a good time when this horror breaks out."
The emotions stirred by reports about the rampage moved many to express their condolences, and others to speculate about the political ramifications.
"Hey, Boo" asks: "Will this finally insert gun control into the two presidential candidates' campaigns?" And multiple commenters suggested mandatory training for those purchasing guns.
"... the best chance of weeding out people with violent tendencies would be to make all gun purchasers spend a certain amount of time with a personal safety trainer who could tell if the person is unable/unwilling to operate a gun safely," says "c g," who concludes by adding: "We require people to spend hours and hours training for basic a driver's license - why not require some training for gun use?"
There is also a consistent thread in the comments that better, more accessible mental health care would prevent the use of guns for irrational violence. Says "Alan Roberts:"
"The real tragedy here isn't just a gun issue, it's the way we deal with the mentally ill in this country ... It's a shame, because we blame it on guns, or laws, or liberals, but really it's primarily a lack of mental health treatment. Very sad for all the victims, my heart goes out to them."
Along with the assumption that the gunman was mentally ill, are questions about the definition of terrorism. The FBI has said that there are no indications the attack was a terrorist attack - readers like "chisti da" want to know if that means the shooter had no motivating ideology:
"Just what is the definition of 'terror?' That this happened and is being brushed aside as 'just some regular white dude' is disturbing."
And as happens whenever guns are involved in a major crime, the meaning of the Second Amendment is being vigorously debated.
(Marissa Alioto is an intern on NPR's Social Media Desk.)