Can shutting down the internet stop a riot?

But it is not social media that fuels riots, civil unrest or violent disorder: it’s people, with technology acting as the conduit to behaviour. Let us not forget that the collective effort of Facebook brought together hundreds of people to clean the streets of London following the riots
http://m.zdnet.com/blog/london/two-thirds-of-brits-support-facebook-twitter-shutdown-in-future-riots/728