Wikipedia:Tip of the day/November 30, 2012
Anyone can revert a page to fix vandalism. All revisions of a page back to the first one are stored in the page history. To revert to an earlier version, just select it from the history, edit and save it. When not dealing with obvious vandalism, reverting often is a bad strategy. It alienates other users and provokes edit wars. Stay cool, talk to the user in question directly, or try to resolve issues on the talk page. Please do not revert the same page more than three times within 24 hours (the Three-revert rule). Doing so can lead to a temporary ban against you. Administrators and Rollbackers have a handy "rollback" feature that allows them to instant-revert changes from a user's contributions page. This helps to quickly revert vandalism as well.