The furore over Facebook's change (and reverting) of its user terms illustrates a few points about Internet companies.
(a) In order to be nimble, they will reserve the right to change their terms as easily as possible. There is no way an Internet company can wait for everyone to agree to every change.
(c) Consumer-driven businesses will, at the end of the day, listen to consumer feedback (i.e. customers win, lawyers lose).
From a legal perspective, I can understand why Facebook requires a wide license to display submitted data on a worldwide perpetual basis. Once you post something online, everyone can potentially view it. Just like words spoken can never be returned, something posted can never really be retrieved and it sits on a server somewhere. It would be unfair and unrealistic to require Facebook to remove all information that one has already voluntarily broadcasted to the world.
Facebook does not claim ownership over user data as a license only gives it a right to carry out specific acts. Ownership of intellectual property is different from ownership of chattels like a car or a bicycle. Owning a car or bicycle means someone else cannot use it. With user data, the user still owns it but many others can use the same under a license.
However, justified concern arises when users have specified privacy restrictions--thus, Facebook should stick to its original bargain and respect that. I believe it does, it now has to ensure that the legal language reflects that policy.
On the topic about legal language, I am also reminded that lawyers constantly need to ensure that what they are drafting reflects what their clients intend to say. It may require more effort, but the effort would not be in vain.