"Historical" events happenin over in the UK.
Cameron also said he's considering banning individuals from social media if they are suspected of plotting criminal activity. Many young people in the melees were seen communicating by BlackBerry mobile e-mail and smartphone devices.
"Free flow of information can be used for good, but it can also be used for ill," Cameron said. "And when people are using social media for violence we need to stop them.
"So we are working with the police, the intelligence services and industry to look at whether it would be right to stop people communicating via these Web sites and services when we know they are plotting violence, disorder and criminality," he said.
He later told reporters Home Secretary Theresa May would hold meetings with Facebook, Twitter and BlackBerry maker Research in Motion to discuss their responsibilities to prevent future incidents.
Interestingly enough, transit authorities in the Bay Area thwarted a planned protest by cutting off cell phone service at several BART stations yesterday.