In Wikipedia's continuing efforts to thwart vandalism, a new semi-protection designation has been approved for high profile articles that have been subjected to malicious editing. The policy does not prohibit anonymous editing, nor can it be applied to articles that are likely to be vandalized in the future but have not been yet. Rather, when an article can be cited as a frequent target of content changes which compromises its integrity, "the semi-protection of a page prevents the newest X% of registered users and all unregistered users from editing that page."

Semi-Protection Policy (Wikipedia)
Vandalism On Wikipedia (Wikipedia)