How Sticky Is Membership on Facebook? Just Try Breaking Free - New York Times

"“It’s like the Hotel California,” said Nipon Das, 34, a director at a biotechnology consulting firm in Manhattan, who tried unsuccessfully to delete his account this fall. “You can check out any time you like, but you can never leave.”

It took Mr. Das about two months and several e-mail exchanges with Facebook’s customer service representatives to erase most of his information from the site, which finally occurred after he sent an e-mail threatening legal action. But even after that, a reporter was able to find Mr. Das’s empty profile on Facebook and successfully sent him an e-mail message through the network."