Help:Wikipedia: The Missing Manual/Editing, creating, and maintaining articles/Dealing with vandalism and spam

Although vandalism and spam are constant aggravations, the ongoing efforts of thousands of editors—like you—do a surprisingly good job of minimizing these problems. This chapter explains in detail what you, a Wikipedia editor, can do in terms of spotting and fixing vandalism and spam.

For Wikipedia, the "encyclopedia that anyone can edit," vandalism—the destruction of content or the addition of useless or malicious content—is a constant, ongoing issue. "Anyone" includes cranks, juveniles (of any age) who don't have anything better to do, and those who hold a grudge against Wikipedia because of past blocks or bans. For readers, obvious vandalism casts doubt on the accuracy of Wikipedia articles. If the vandalism is subtle, readers can be deliberately misinformed. For editors, fighting vandalism reduces the amount of time available to improve articles.

Spam, at Wikipedia, refers to improper external links added to Wikipedia articles, which is why you often see the term linkspam. Spam is a smaller problem than vandalism because most readers of Wikipedia articles don't follow external links. Still, as Wikipedia becomes more widely read, the temptation grows to add links in the hopes that someone will click them, generating traffic for the spamming Web site. (See the box below for more detail on the differences between vandalism and spam.)

Fighting vandalism and spam is a bit like doing detective work: In addition to figuring out who did what (Chapter 5: Who did what: Page histories and reverting), you investigate the extent of the problem, assess the possible underlying motives of the perpetrator (that affects things like warning levels), and then decide what to do (warn, request a block, and so on). It's important work, and many editors specialize in it.