Wikipedia claims to be a free encyclopedia that anyone can edit. And that’s exactly what it is. Its name comes from the Hawai‘ian wiki, or quick: a wiki is any collaborative, easily-edited web page. You hear people using Wiki as a nickname for Wikipedia, but that’s not really correct: the foundation that runs it also hosts its siblings Wikinews, Wikiquote, Wiktionary and so on.

Wikipedia was only set up in 2001, but now has over 3 million articles, all written by unpaid volunteers. It’s startlingly comprehensive, if not always well written. It reflects its geeky origins: 11,697 words on Gondor, compared with 6,751 on Ghana. And it seems to have dealt a death blow to the traditional printed encyclopedia. What might be the project, in its infancy today, that will have transformed the way we do research in another eight years?

A good introduction is the history of Wikipedia in the Sept 2006 Atlantic Monthly, which prompted a personal testimonial from Nicholson Baker, in which he reveals himself to be an ardent inclusionist. The inclusionist/deletionist split is a major philosophical conflict in Wikipedia, between those who demand that article subjects be “noteworthy” (which in practice means cited in the mainstream media) and others who believe there’s room in Wikipedia for almost anything; inclusionists like Baker scour the list of articles marked for deletion and add citations to try to save them.

People are always amazed that they or anyone else can click on a Wikipedia page and change the content, and I have to reassure them that it’s legal—indeed, encouraged. They always then ask why the pages aren’t full of digital graffiti and silliness. To see how Wikipedia protects itself, look at the History pages for a typical article: on Baldwin Street, the steepest street in Dunedin and likely the world. On July 20, 2009, an anonymous visitor clicked on Edit and cautiously added an ungrammatical The to the beginning of one section. They clicked save and were no doubt amazed to see their changes appear in the entry. Emboldened, they changed The to penis. Hilarity doubtless ensued. Until, less than a minute later, a piece of software called ClueBot sniffed out the offending word and politely reverted all their edits. Undeterred, the vandals typed in the word JOSH. A minute later, this was deleted by a human being, username Vicenarian (American, male, 24, Unitarian according to his user page). BEN ROX UR JOX typed the vandals. Vicenarian deleted it. The vandals responded with a half-hearted from ben & josh. This was deleted by user Snigbrook (from Lancashire, supports the Blackburn Rovers) a few seconds later. No response. Ban and Josh had no doubt quit in disgust. The entire episode lasted seven minutes.

That’s how vandalism is taken care of. Wikipedia sceptics are also suspicious of the accuracy of the content, though. How can we be sure the information is accurate? Well, as Professor Peter Murray-Rust puts it, “the bit of Wikipedia that I wrote is correct.” There are plenty of experts adding and editing content, and the sheer weight of numbers seems to make articles gradually converge on accuracy. Wikipedia’s great advantage is that it’s absolutely up to date, and errors can be easily corrected, neither of which are true of textbooks or encyclopedias. It’s possible for inaccuracies to sneak in, especially if people start editing their own page to minimise their alleged naughtiness, as Richard Worth did earlier this year. Sadly he did so under a fairly recognisable login name, and was shamed in the media for it.

• An interview with one of the early Wikipedians
• Students surveyed on how they used Wikipedia (YouTube video)
• The official Policies and Guidelines of Wikipedia, to counter any suspicion that anarchy prevails
• A list of fifty fascinating Wikipedia articles, and fifty more, to give you an idea of its scope
• A recent report suggests the explosive growth of Wikipedia is slowing, and editing of what’s already there is becoming more important: here’s a summary, and an older analysis of who actually writes Wikipedia.
• A nice short think piece by Cory Doctorow.