Wikipedia: The Missing Manual

Reverting Vandalism and Spam

If you simply revert a vandalizing or spamming edit, and then go about other business, you’ve missed a major opportunity to find other vandalism and spam by the same editor. Worse, you’ve made it less likely that other editors will check the edit history of that editor in the future, looking for vandalizing and spam, and if indeed there are such problems, you’ve given the problem editor more time to continue with destructive editing.

To handle vandalism and spam the way experienced editors do, you should do three things in addition to reverting the problem edit: determine if that editor has other problem edits, and deal with those as well; post an appropriate warning to the editor; and, in extreme cases, ask an administrator to block the problem editor. Experienced editors also know how to ask that a page be protected if it’s repeatedly vandalized by a number of different (typically, anonymous IP) editors.

This chapter shows you the right way to approach what looks like vandalism. For the mechanics of identifying and reverting a problem edit, flip back to Chapter 5.

Most vandalism is obvious. But when you encounter something you’re not sure about, Wikipedia’s guidelines suggest that you assume good faith in assessing the edits of others. (Details at WP:AGF.) That doesn’t mean that you should excuse vandalism and spam; it means that when you encounter something that’s in a gray area, investigate further, as described in this section. If ...