http://www.bbc.co.uk/news/uk-23494920
Just been listening to some of the horror stories from these keyboard warriors. Surely Twitter et al can just insist on proper ID, then it's game over, isn't it?
Trolling Mary Beard, for heaven's sake. She retweeted it. It also seems one of his followers knew him and threatened to send the offending tweet to his mum. He backed down in a great hurry.
Hoiwever, this seems to have depended on him using his real name (and having a mum who'd give him a good smack).
Digitalspy would only allow you to register if you provided an email address from your ISP, like @sky.com, any other email registration had to pay a fee to activate membership., maybe something like that might work.