Illustration: Harry Campbell

Wikipedia users who logged on to the free online encyclopedia this January to do research on current members of the U.S. Congress may have been surprised to encounter the online equivalent of a playground shouting match. The official entry for Rep. Eric I. Cantor (R-Va.) noted that he smelled of "cow dung," and the blurb for Sen. Tom Coburn (R-Okla.) mentioned a dubious-sounding biographical detail: "Coburn was voted the most annoying senator by his peers in Congress. This was due to Senator Coburn being a huge douche bag."

Within hours, Wikipedia administrators had intercepted the renegade edits—but not before the incident provoked a nationwide media furor, spurring questions about the encyclopedia's credibility. As the first-ever major reference work with a democratic premise—that anyone can contribute an article or edit an entry—Wikipedia has generated shared scholarly efforts to rival those of any literary or philosophical movement in history. Its signature strength, however, is also its greatest vulnerability. User-generated articles are often inaccurate or irrelevant, and vandals like the political jokesters are a constant threat. As a result, the role of the encyclopedia's gatekeepers assumes added importance. Who are they, and how do they go about the business of deciding which new content will pass through their crucible?

Founded in 2001 by Jimmy ("Jimbo") Donal Wales, a former Chicago options trader, Wikipedia has morphed into a cultural phenomenon on a par with Google or Friendster. Internet users have contributed more than 3 million articles in 200 languages to the site, and every few seconds, a new article or edit is added to Wikipedia's 180-gigabyte database. Overseeing the entire gargantuan knowledge machine are the Wikipedia elite: about 800 longtime contributors who have volunteered to maintain the site and help ensure its accuracy.

The influx of information is so great that it's easy to characterize content-control efforts as potshots into a crowd, but Wikipedians—as regular contributors like to call themselves—claim the review process is actually carefully executed and multilayered. The first line of defense is the so-called recent changes patrol, an online SWAT team made up of hundreds of volunteers who comb new or recently modified content for errors. "If there's outright vandalism, the recent changes patrol will avert the situation fairly quickly," Wales says. "An easy deletion would be an article with the title 'asdfasdf' and content reading 'Hi Mom.'"