In follow up to my previous post, "Delete your Facebook now":
Well, the message has spread, and Facebook has backed down, reverting for now to its previous terms of use. Crucially, the "You may remove your User Content from the Site at any time" paragraph has been restored, and I believe the following clarification is new:
Facebook does not assert any ownership over your User Content; rather, as between us and you, subject to the rights granted to us in these Terms, you retain full ownership of all of your User Content and any intellectual property rights or other proprietary rights associated with your User Content.
— "Terms of Use", Facebook, as of 18 Jan 2009.
(Not that that was my concern anyway, as I do understand the difference between irrevocable use rights and outright ownership.)
I don't know if I'll be restoring my Facebook account — it depends mostly on what the new Terms look like. The whole thing gave me a bit of a scare, and I'll be a lot more careful in future.