Here's an interesting idea that just crossed my mind. Rather than look at the situation in legalistic terms, let's think about social contracts. Can we encourage people to agree to a code of conduct that prohibits removal of content?

Consider the following changes to the site that parallel Amazon's "Real Names" system:

• Allow everybody to delete their own posts by default.
• However, after attaining a certain level of experience, each user can make an irrevocable election to join the "Order of the Monks of Conviction," at which time they must agree to stand by their words for all time, give up their deletion privileges, and allow for the site to track and make publicly available the change history of their comments.
• To encourage users to join the Order of the Monks of Conviction, we can display a Monks-of-Conviction badge next to the names of members of the Order, wherever they may appear on the site. (We can also give members free beer and the like.)

What do you think?

Cheers,
Tom