Social censorship?

Not so long ago, in the aftermath of the Manchester riots, we mused on social media, censorship, and its use both negatively within Britain’s urban disturbances and positively in the context of the Arab Spring. Now¬†Feather Brooksbank’s latest media update highlights a story in The Guardian that proves we were, understandably, not alone in our train of thought.
During the aftermath Blackberry manufacturer RIM, Facebook and Twitter were all called to meet with the Home Secretary Theresa May as a result of David Cameron’s proposals to clamp down on the social networks. Apparently now that’s not going to happen, with plans to ban suspected rioters from the platforms when any similar situations arise abandoned. Just how they thought such potential troublemakers could be profiled is anyone’s guess, but ultimately despite the change of tact the issues still remain. So what do you think- should we have tighter monitoring of such online communities, and if so, how can this be done while still retaining plurality and freedom of speech?