The social media push to highlight imbalance between men and women follows the death of 22-year-old Elliot Rodger, who allegedly stabbed to death three men in his Santa Barbara apartment, before going on a shooting rampage nearby and killing two young women and another young man.
Another 13 people were wounded in the attack in California.
In a nearly seven-minute YouTube rant titled Elliot Rodger's Retribution, the 22-year-old said he would have "revenge" for being ignored by women.
"I've been forced to endure an existence of loneliness, rejection and unfulfilled desires, all because girls have never been attracted to me," he says.
"... I don't know why you girls aren't attracted to me, but I will punish you all for it."
He says he will "punish all" for ignoring him.
Similar frustrations were outlined in his manifesto, a 141-page document outlining his "Day of Retribution" which was posted online. It can be read in full at the end of this article.
Online reaction around the world
The rampage has since been described as an "anti-woman shooting spree", prompting a growing conversation among Twitter users about the experience of being a woman in a culture that makes them feel unsafe.
Feminist website Jezabel said the hashtag #YesAllWomen was "uprooting everyday sexism" in the wake of the shooting, carried out by a man who resented women for rejecting him and men for not sharing his rejection.
The hashtag has also been described by TIME as an outlet for women to "criticize the way society teaches men to feel entitled to women at the expense of their health, safety and, in Rodger’s case, lives".
The stories posted by both men and women have highlighted issues aorund sexual harrassment, abuse and everyday sexism in a culture where women "are taught to talk to their cars with their keys between their knuckles".
The hashtag #YesAllWomen was trending in Australia on Monday morning, as mourners gathered on the other side of the world for vigil services.
Some users have also hijacked the hashtag to harrass women tweeting in support, prompting online backlash.
