For Silicon Valley companies that must balance the right to free speech with the risk of empowering and broadcasting abhorrent beliefs, the violence in Charlottesville has been a clarifying moment.

In a cascade of notes to employees and public statements, technology executives rushed to condemn the hatred and bigotry that underlay an attack on protesters who were rallying against a white supremacist march in Virginia. Apple CEO Tim Cook specifically denounced Donald Trump for asserting “a moral equivalence between white supremacists and Nazis, and those who oppose them” and told his employees the company would match donations to anti-discrimination groups to which he was personally directing $2 million.

There were more concrete developments than C-suite condemnations. One after another, companies moved to cut off services to customers linked to the bloodshed and to the constellation of beliefs surrounding it - or, at the minimum, to reiterate that they could.

Domain name service provider GoDaddy said it would no longer work with the neo-Nazi forum Daily Stormer, as did Google and Cloudflare, whose CEO called the site “reprehensible”.

Facebook CEO Mark Zuckerberg vowed in a post that the company would be vigilant in removing posts that promote “hate crimes or acts of terrorism.” PayPal released a statement saying it would not provide services to groups like the Ku Klux Klan or Nazis that "promote hate, violence or racial intolerance", and Apple nixed Apple Pay support for websites that sell white supremacist apparel. Uber said in a statement that it opposed “discrimination of any kind” and retained the right to ban users from the app.

Even the dating app OKCupid piled on, saying in a tweet that after discovering a white supremacist using the app, “Within ten minutes we banned him for life.”

In explaining those moves, companies said they were simply hewing to preexisting policies that govern how their services are used and prohibit violent threats.

“This is not a shift or new policy, just a reiteration of our existing commitment to remaining vigilant against the advancement of hate, intolerance and violence on our platforms,” PayPal spokesman Justin Higgs said in an email.

Violence on the streets of Charlottesville Show all 9 1 /9 Violence on the streets of Charlottesville Violence on the streets of Charlottesville Protesters clash and several are injured White nationalist demonstrators clash with counter demonstrators at the entrance to Lee Park in Charlottesville, Virginia. A state of emergency is declared, August 12 2017 Violence on the streets of Charlottesville Trump supporters at the protest A white nationalist demonstrator walks into Lee Park in Charlottesville, Va., Saturday, Aug. 12, 2017. Hundreds of people chanted, threw punches, hurled water bottles and unleashed chemical sprays on each other Saturday after violence erupted at a white nationalist rally in Virginia. AP Photo Violence on the streets of Charlottesville State police stand ready in riot gear Virginia State Police cordon off an area around the site where a car ran into a group of protesters after a white nationalist rally in Charlottesville, Virginia AP Photo Violence on the streets of Charlottesville Militia armed with assault rifles White nationalists, neo-Nazis and members of the 'alt-right' with body armor and combat weapons evacuate comrades who were pepper sprayed after the 'Unite the Right' rally was declared a unlawful gathering by Virginia State Police. Militia members marched through the city earlier in the day, armed with assault rifles. Getty Images Violence on the streets of Charlottesville Statue of Confederate General Robert E Lee The statue of Confederate General Robert E. Lee stands behind a crowd of hundreds of white nationalists, neo-Nazis and members of the 'alt-right' during the 'Unite the Right' rally 12 August 2017 in Charlottesville, Virginia. They are protesting the removal of the statue from Emancipation Park in the city. Getty Images Violence on the streets of Charlottesville Racial tensions sparked the violence White nationalists, neo-Nazis and members of the 'alt-right' exchange insults with counter-protesters as they attempt to guard the entrance to Lee Park during the 'Unite the Right' rally Getty Violence on the streets of Charlottesville A car plows through protesters A vehicle drives into a group of protesters demonstrating against a white nationalist rally in Charlottesville, Virginia. The incident resulted in multiple injuries, some life-threatening, and one death. AP Photo Violence on the streets of Charlottesville Rescue personnel help injured people after a car ran into a large group of protesters after an white nationalist rally in Charlottesville, Virginia AP Photo Violence on the streets of Charlottesville President Donald Trump speaks about the ongoing situation in Charlottesville, Virginia from his golf club in Bedminster, New Jersey. He spoke about "loyalty" and "healing wounds" left by decades of racism.

But the rush of tech firms announcing their right to refuse service to avatars of hate could signal a larger change underway, business experts predicted, with Silicon Valley now facing a heightened expectation of policing violent views.

“Particularly in the Valley, they’re all about freedom and not being the arbiters of opinion,” said Kellie McElhaney of the Center for Responsible Business at UC Berkeley. “But now that is changing and they are taking a stand.”

Companies likely felt compelled to act stand in part because of pressure from customers and from employees, said Ms McElhaney, who recounted hearing from tech workers “demanding” their employers draw a line. But firms that have positioned themselves as altruistic drivers of innovation have also set a high bar.

“There’s an evangelist streak to a lot of the companies that get attention…the goal is to make the world a better place through better geo-location apps, for example,” said Jo-Ellen Pozner, a fellow in the Markkula Center for Applied Ethics at Santa Clara University’s Leavey School of Business. “If you’re putting that in a front and center in your corporate mission and vision and the communications you have internally and externally, and you’re confronted with a value-based challenge - you said you’re a company that wants to make the world a better place, and now you have to do it.”

“Even if there is really only a public statement with no underlying action, that is important,” Ms Pozner added. “I’m not so cynical to think this is all window-dressing.”

The cast of Detroit discuss Charlottesville violence

Debate has raged for years over the responsibility that comes with running a global platform that allows ideas to spread and groups to organise regardless of their aims. Some tech companies, particularly Facebook and Twitter, have faced criticism in the past for not being quick enough to ban users or scrub content that harasses others or incites bigotry.

“What they’re doing now, I think, is laudable, but it doesn’t come out of nowhere,” said Joseph Holt, a professor of business ethics at the University of Notre Dame. Companies have tried to resolve the tension between two competing ideals, Mr Holt said: “we’re neutral, we just host the sites, we don't supply the content” versus “these other values around protecting users from violence and just general civility.”

“I think a lot of values are getting a little more weight now,” Mr Holt said. “It seems clear that some of what the companies are doing is a response to social pressure - but I don't think the social pressure is what makes them espouse a value. It just gives more weight to the other side of the equation. How deep and lasting a change that is I think remains to be seen.”

Those competing priorities were evident in GoDaddy’s justification for booting Daily Stormer. While the company said it generally supports free speech, even in the case of sites offering “tasteless, ignorant content,” Daily Stormer crossed the line by violating a prohibition on “promoting, encouraging, or otherwise engaging in violence.”

Where companies draw that line is now likely to come under more scrutiny. The risk, Mr Holt said, is that companies swing too far in one direction and begin censoring or blocking potential customers before they’ve done anything objectionable, “where companies preemptively removed a company, kicked them off the web, took away their domain name because given their ideas they might say something that incites violence.”

That possibility was not lost on Cloudflare CEO Matthew Prince. Even as he defended severing ties with Daily Stormer, saying in a CNBC interview that “life was too short to deal with jerks like this,” Mr Prince cautioned that tech firms wield significant power to shape what type of speech survives in the world.

“What I’m concerned about is that technology companies like Facebook, like Google, like Cloudflare, that control huge swaths of the Internet,” could “make a determination without any kind of legitimacy or political responsibility and literally wipe someone off the Internet,” Mr Prince said.

Striking the right balance is going to be an ongoing process that requires examining cases one by one, said Ms McElhaney, who acknowledged the peril of tumbling down a “slippery slope.” But she said tech companies did not have the option to stay idle.