The Isla Vista, California, killings, which police say were committed by Elliot Rodger, have spurred discussion across the world about systematic misogyny and relations between the sexes in the United States.

Many women (and men) have taken to social media with the hashtag #YEsAllWomen to share personal stories of sexual assault, misogyny and sexism.

Unsurprisingly, there’s been some resistance to #YesAllWomen, but overall it’s provided not only an outlet for women to discuss women’s issues, but a catalyst for discussion and reflection across the Internet. The topic has trended all day Sunday and doesn’t seem to be slowing down.

For niche online communities that Rodger apparently frequented and where he may have developed some of his extreme views, the shooting has brought newfound and unwelcome scrutiny.

Some are blaming movements like Men’s Rights, “The Red Pill” (TRP) and "seduction communities" for Rodger's views. Men’s Rights advocates argue that men are not treated as equals compared to women in certain aspects of society. TRP on Reddit describes itself as a “discussion of sexual strategy in a culture increasingly lacking a positive identity for men.” The so-called seduction community consists of scores of YouTube pickup artists and forums dedicated to helping men seduce women.

Critics say these communities foster misogynist views, but many in the groups argue their discussions are harmless and seek only to benefit men, not hurt women. While any community has its spectrum of moderate and radical members, the California killings brought a new level of gravity to the table that many (including critics of the communities) haven’t dealt with in the past.

Few, if any, condone Rodger's alleged murder spree. It's hard to blame an anonymous "community" for one man's violent acts, but these groups will have to face tough scrutiny, tougher than usual. These communities are often chastised, but the discussion has never been as intense as it is now. Many members are now distancing themselves from the extreme elements to save face for themselves and the community as a whole.

For many the question remains: Where did Elliot Rodger foster his beliefs? Many anonymous posters don’t hesitate to half-heartedly advocate violence and that’s nothing new, nor is it limited to the communities in question. But are these communities at any fault if one of their members takes their ideas, twists them and uses them to justify a massacre? Expect this to be a major topic of discussion in the future.

There also have been some less-than-scientific opinions voiced on Elliot Rodger’s mental condition, even though it's no mystery that he was getting professional help:

RapGenius co-founder Mahbod Moghadam had some questionable comments about Rodger’s manifesto, “My Twisted World.”

Elliot Rodger certainly isn't the first sexually frustrated man to resort to violence. A 48-year-old man killed Heidi Overmier, Elizabeth Gannon and Jody Billingsley and himself at a Pennsylvania gym for nearly the same reasons Rodger went on his spree. He too kept a blog about his frustrations and plans. In 1989, a Canadian man killed 14 women in a school in Montreal. He said in his suicide note that feminists "ruined my life."