Posting anything on Facebook becomes Facebook's property forever!
Accroding to the "Consumerist" anything you upload to Facebook can be used by Facebook in any way they deem fit, forever, no matter what you do later. Want to close your account? Good for you, but Facebook still has the right to do whatever it wants with your old content. They can even sublicense it if they want.
Excerpt from the new user aggreement:
"The following sections will survive any termination of your use of the Facebook Service: Prohibited Conduct, User Content, Your Privacy Practices, Gift Credits, Ownership; Proprietary Rights, Licenses, Submissions, User Disputes; Complaints, Indemnity, General Disclaimers, Limitation on Liability, Termination and Changes to the Facebook Service, Arbitration, Governing Law; Venue and Jurisdiction and Other."
Link: http://consumerist.com/5150175/facebooks-new-terms-of-service-we-can-do-anything-we-want-with-your-content-forever