Jessica Guynn

USA TODAY

SAN FRANCISCO — On Sunday night, Hadas Gold, a Politico media writer, began receiving threats on Twitter. One image superimposed a yellow star of David on her shirt and a bloody bullet hole in her forehead. Another photoshopped her face on a corpse in a concentration camp oven.

The message that came with the photos: "Don’t mess with our boy Trump, or you will be first in line for the camp."

Gold, whose grandmother fled Poland with her family weeks before Jews from their neighborhood were deported to concentration camps and whose grandfather lost about half of his extended family in the Holocaust, notified Twitter, which moved quickly to suspend the accounts.

Gold says these incidents have become increasingly common "the more we wrote about Trump, and the more we wrote about his rhetoric."

A report this week from The Anti-Defamation League documented the rise in anti-Semitic tweets targeting journalists who cover the Republican presidential candidate. From August 2015 to July 2016, the ADL found 2.6 million tweets with anti-Semitic language. Of those, nearly 20,000 tweets were directed at 50,000 journalists in the U.S., with more than two-thirds of the tweets sent by 1,600 Twitter accounts.

Words that appear frequently in the profiles of these Twitter accounts: Trump, nationalist, conservative, white.

"The report is representative of the bigotry and hatred that we are seeing play out on a broader scale," said Oren Segal, director of ADL's Center on Extremism and an author of the report.

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This turbulent election season has fanned the flames of racism, xenophobia, homophobia, sexism and bigotry. Hate speech that typically resides in the dark recesses of the Internet has bubbled into the mainstream and onto Twitter, a popular online hangout for journalists and politicians such as Trump, who has millions of followers there. Because people don't have to use their real names on the service, they can attack people of color, women, Muslims and other groups with relatively little risk.

"This is only a fraction of what's happening online right now as a result of the legitimacy various extremist ideologies have been given in this campaign season," Ryan Lenz, editor of the Southern Poverty Law Center's Hatewatch blog, said of the ADL report. "We have seen a massive rise of hate speech."

Spokeswoman Hope Hicks says the Trump campaign has "no knowledge of this activity" and strongly condemns "any commentary that is anti-Semitic."

"We totally disavow hateful rhetoric online or otherwise," Hicks wrote in an emailed statement.

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Conversations that take place on Twitter, famous for its 140-character limit, tap into the nation's pulse, be it the protests on the streets of Ferguson, Mo., the Congressional sit-in over gun control or the launch of Beyonce's Lemonade album. But more and more, people venturing onto the service to catch up on news or with friends are confronted with hatred and bigotry spewed by the fringes of society, Segal says.

"When there is such a volume, we have to ask ourselves what can we do? What can the Internet service providers do? What can vast segments of society do? So that we hold people accountable and create safe spaces online the way we expect those spaces to be in the real world," he said.

For years Twitter has faced sharp criticism for not aggressively enough policing abuse and harassment on its service. Twitter says its rules "prohibit inciting or engaging in the targeted abuse or harassment of others."

Yet, if anything, abuse has increased.

In one of the highest-profile incidents, Leslie Jones, who starred in the all-female remake of the Ghostbusters movie, temporarily left Twitter after being targeted by racist trolls — anonymous online users who harass other users — who compared her to primates including Harambe, the gorilla shot dead in May at the Cincinnati zoo. "Ok I have been called Apes,” she wrote on Twitter at the time, "even got a pic with semen on my face. I’m tryin to figure out what human means. I'm out."

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Trump's inflammatory rhetoric and policy positions have made many groups feel unsafe on Twitter, they say. Trump has suggested banning Muslims from entering the U.S., has said "Islam hates us," suggested the surveillance of mosques, and has talked about "profiling" of Muslims as a response to terrorism.

Trump has "mainstreamed Islamophobia in our nation," said Ibrahim Hooper, communications director for the Council on American-Islamic Relations.

"He's given permission to all those who held anti-Muslim views, or who might have formed anti-Muslim views recently, to go public with them quite proudly," Hooper said. "Whereas before maybe they would have been reluctant to be so open about their bigrotry, now you have a major American public figure saying that's perfectly OK. In fact it's somehow patriotic."

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Irfan Chaudhry, a criminology instructor at MacEwan University in Edmonton, Canada, who has researched racism on Twitter, says these disturbing attacks typically grow in numbers and intensity during a presidential election. The difference: In 2016 there are far more people on social media than there were in 2012.

"During the last presidential election, a lot of people were still trying to get a handle on what social media is," Chaudhry said. "Now they know what it is, and now we are able to utilize it in more data-driven and analytical ways that give us these insights we weren't aware of before."

Leslie Miley, a former Twitter employee, says hate speech has always lurked on Twitter. But the alt-right, the community of activists that embrace white nationalism and supremacy, "has its Twitter game on point right now," he says.

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"They just know how to use it — not just to communicate with each other and organize, but also to refine their message and push their agenda. It's scary how effective they are," Miley said.

Of all the groups targeted, observers say Jewish journalists are getting the brunt of hate speech from Trump supporters. The anti-Semitism is coordinated in a way it has not been against any other group, said Sophie Bjork-James, a post-doctoral fellow in the anthropology department at Vanderbilt University.

"While various groups have been targeted with hate speech on Twitter during this election, I don’t think anything compares to what Jewish journalists are going through," Bjork-James said. "Many white nationalists have been inspired by the Trump campaign to increase their involvement, and a central part of this ideology is anti-Semitism."

Unlike other social media services, Twitter does not actively monitor for language that violates its policies and relies instead on users to flag it. It has also gotten a bad rap for being slow to respond to complaints or for responding to them inconsistently, especially when they do not come from high-profile users.

Under CEO Jack Dorsey, Twitter says it's developing new tools to clamp down on the lack of civility. Twitter also says it's continuing to "invest heavily" in improving its enforcement systems to identify abuse and take swifter action.

"We are reviewing our policies to prohibit additional types of abusive behavior and allow more types of reporting, with the goal of reducing the burden on the person being targeted," the company said in a statement.

That effort is taking on greater urgency as rampant abuse undercuts Twitter's business.

Twitter has struggled as competitors Facebook, Instagram and Snapchat encroached on its turf and spirited away users and advertising dollars. Twitter, which has a market value of about $12 billion, is also losing money.

Those were key factors in Walt Disney Co. deciding not to pursue a bid for Twitter. The other? Concern that the abuse and harassment on the service would mar Disney's wholesome image.