SAN FRANCISCO – Twitter, the Web-based social-messaging service, helped spur a 30 percent growth in online forums for hate and terror over the past year, according to a report by the Simon Wiesenthal Center.
The center is currently tracking about 20,000 hate and terror-related sites, up from 15,000 a year earlier, according to a report set to be presented Wednesday at a briefing in Washington, D.C.
Social-media services including Twitter, Facebook and Google's YouTube video-sharing website should restrict the dissemination of hateful speech or content that aids terrorists, according to Rabbi Abraham Cooper, associate dean at the Simon Wiesenthal Center, a Los Angeles-based human-rights advocacy group. Events such as the Boston Marathon bombings highlight the need for some content to be blocked, Cooper said. U.S. officials have said the attackers were motivated by radical Islamic teachings on the Internet.
"Twitter is allowing itself to be one click away from full libraries of terrorist material," Cooper said in an interview.
While Facebook and other Internet companies have met regularly with Cooper's organization to address concerns related to content, Twitter has not, according to the report.
Jim Prosser, a spokesman for San Francisco-based Twitter, said that the company supports a global communication service with a variety of voices, ideas and perspectives.
"As a policy, we do not mediate content or intervene in disputes between users," he said in an e-mailed statement. "However, targeted abuse or harassment may constitute a violation of the Twitter rules and terms of service."
The growth rate in Web-based hate speech may be slower than the gains in use of social media. Twitter, for example, tracked more than 400 million posts a day in November, twice the activity level from June 2011, Prosser said.
Social-networking sites face difficult questions in balancing their users' right to free expression with rules against hate speech written into their terms of service. Last October, Twitter blocked access to the account of a banned German right-wing group for viewers from that country, the first time the microblogging service has made use of an option to withhold content.