The New York Times' Maria Aspan has written an article on how hard it is to really delete your Facebook account:
Some users have discovered that it is nearly impossible to remove themselves entirely from Facebook, setting off a fresh round of concern over the popular social network’s use of personal data.
While the Web site offers users the option to deactivate their accounts, Facebook servers keep copies of the information in those accounts indefinitely. Indeed, many users who have contacted Facebook to request that their accounts be deleted have not succeeded in erasing their records from the network.
The technological hurdles set by Facebook have a business rationale: they allow ex-Facebookers who choose to return the ability to resurrect their accounts effortlessly. According to an e-mail message from Amy Sezak, a spokeswoman for Facebook, “Deactivated accounts mean that a user can reactivate at any time and their information will be available again just as they left it.”
And thus privacy and data ownership continue to be the most important debate 'n discussion topics in the evolving social media space.