Wikipedia: The Missing Manual

Reverting Edits

If you’re reading an article in Wikipedia and see vandalism, unencylopedic links to commercial or personal Web sites (linkspam), or some other blatant policy violation, your first impulse may be to click “edit this page” and fix the problem. Resist that urge. Manually deleting offending text is error-prone and time-consuming. And, worst of all, if the vandal or spammer deleted or overwrote text while doing the dirty deed, simply removing the problem still leaves the article damaged, since good information is now missing.

Instead, use options in the page history to revert the problematic edit(s). Reverting restores any content that was overwritten or deleted, and removes offending text, putting the article back to what it was before it was vandalized or spammed. Reverting is one of the most powerful features of wiki software. This section shows you how to do a revert in just a few easy steps.

Note

On the other hand, reverting isn’t always the answer. If another editor adds text that you think is verbose, or is full of spelling errors, or has invalid citations (to name just a few possible problems) to an article, you should edit, not revert. Keep what’s useful, improve what’s marginal, and delete what’s not useful. Restrain your reverts to bad faith edits—clear vandalism and spam, and to clear policy violations, and you’ll get along well with all the other editors helping to improve Wikipedia.

Two Options: Revert to a Prior Version and Undo

Until November 2006, Wikipedia ...