Paywalls are essential, says ad man Sorrell

British advertising mogul Sir Martin Sorrell claims online paywalls will be "essential" if publishers want to make money in the digital age. The CEO of communications (and basket-making) company WPP threw his wholehearted support behind the pay-to-view technology being employed by Rupert Murdoch's News International on the websites of UK newspapers The Times and Sunday Times. "We think paywalls are essential because we think giving away content for free, particularly...