Facebook, Google and Twitter told Congress Wednesday that they've gone beyond screening and removing extremist content and are creating more anti-terror propaganda to pre-empt violent messages at the source.
Representatives from the three companies told the Senate Committee on Commerce, Science and Transportation that they are, among other things, targeting people likely to be swayed by extremist messages and pushing content aimed at countering that message. Several senators criticized their past efforts as not going far enough.
"We believe that a key part of combating extremism is preventing recruitment by disrupting the underlying ideologies that drive people to commit acts of violence. That's why we support a variety of counterspeech efforts," said Monika Bickert, Facebook's head of global policy management, according to an advance copy of her testimony obtained by CNBC.
Bickert said that in addition to using image matching and language analysis to identify terror content before it's posted, the company is ramping up what it calls "counterspeech."
Facebook is also working with universities, nongovernmental organizations and community groups around the world "to empower positive and moderate voices," Bickert said.
Google's YouTube, meanwhile, says it will continue to use what it calls the "Redirect Method," developed by Google's Jigsaw research group, to send anti-terror messages to people likely to seek out extremist content through what is essentially targeted advertising. If YouTube determines that a person may be headed toward extremism based on their search history, it will serve them ads that subtly contradict the propaganda that they might see from ISIS or other such groups. Meanwhile, YouTube supports "Creators for Change," a group of people who use their channels to counteract hate.
The video site is also adapting how it deals with videos that are offensive but don't technically violate its community guidelines, putting this so-called borderline content behind interstitials and removing comments, according to the testimony of Juniper Downs, YouTube's head of public policy.
Downs said that over the past year YouTube's algorithms, in concert with human reviewers, have been able to remove hateful content faster than before.
"Our advances in machine learning let us now take down nearly 70% of violent extremism content within 8 hours of upload and nearly half of it in 2 hours," Downs said.
Twitter's Carlos Monje Jr., director of public policy and philanthropy in the U.S. and Canada, said the company has participated in more than 100 trainings events since 2015 on countering extremist content.
Those training sessions included events in Beirut, Bosnia, Belfast and Brussels and summits at the White House, the United Nations and in London and Sydney, Monje said in his prepared testimony.
The U.S.-based tech giants have come under fire in the U.S. and Europe for allowing their websites to be used by Islamic terrorists and other extremists for recruiting and propaganda.
The German government passed a law last year that fines internet companies for allowing hate speech to remain on a site for more than 24 hours. Leaders in France and the U.K., which have suffered a series of terrorist attacks, have threatened similar action.
Now the companies are feeling the heat in Washington after revelations that extremists are using their services to recruit and target Americans.
A November report from New York University's Stern Center for Business and Human Rights estimated the Islamic terrorist group ISIS generated 200,000 social media messages every day.
An investigation by CNBC, meanwhile, found dozens of accounts on Facebook and Google Plus being used by terrorists to promote their message. Some of those accounts had been taken over by hackers first.
They also created an industry-wide group, the Global Internet Forum to Counter Terrorism, to share data on extremist groups. The forum said in December its database had 40,000 images and videos which it was using to screen content from their sites.
"Social media companies realize the damage of these bad actors far too late," says Clint Watts, the Robert A. Fox Fellow at the Foreign Policy Research Institute, who is also scheduled to testify at Wednesday's hearing.