10% of the Daily Mail's UK traffic is generated by referrals from Facebook

"Martin Clarke, the Daily Mail executive who runs Mail Online, revealed today that 10% of the website's UK traffic is generated by referrals from Facebook, a "gigantic free marketing engine".
Clarke told delegates at the Society of Editors annual conference in Glasgow that only Google directs more UK traffic to Mail Online and urged newspapers to embrace social networking sites including Facebook and Twitter.
"The social networks are becoming increasingly important to us," Clarke said. "If you want an engaging site, Facebook isn't a threat or a parasite but a gigantic free marketing engine.""

Source:  The Guardian, 15th November 2010