THE internet's omniscience is one of its most useful and transformative features [Citation needed]. Whether you want to look up an obscure word or phrase, get a quick briefing on an historical figure or dig into a little-known scientific or political concept [Example needed], help is just a click away. In part this is because of the power and reach of Google's search engine; but search is only as useful as the information it retrieves, and for many common queries the top match will be an entry in Wikipedia, an online, user-generated encyclopedia which celebrates its tenth birthday this week (see article).

Wikipedia started life as an offshoot of Nupedia, a free, online encyclopedia being written by experts. To speed up the production of articles, two members of the Nupedia team, Larry Sanger and Jimmy Wales [see Wales (disambiguation)], had the idea of allowing anybody to edit entries, using “wiki” technology. The result quickly eclipsed Nupedia.

It is an astonishing success story [Further explanation needed]. On paper, the idea that volunteers could collectively produce the largest and most popular encyclopedia the world has ever seen sounds implausible. Surely reference works need to be compiled by experts [Disputed]? Yet Wikipedia now has over 17m articles, 3.5m of them in English, and its popularity—it is one of the ten biggest sites on the web and is used by around 400m people each month—shows how much people value it. As well as being a useful reference work, Wikipedia is also the most striking example of the idea that volunteers working together online can collectively produce something valuable. Not everyone can contribute to (or even understand) open-source software projects, but anyone can see how Wikipedia's “crowdsourcing” model works. It showed that the wisdom of the masses could be harnessed, inspiring many other crowdsourced projects—a further reason to celebrate its success [This article reads like an editorial or opinion piece and may require cleanup].

For all Wikipedia's achievements, however, it inspires three worries: that it contains too many inaccuracies; that it is not financially sustainable; and that it has lost touch with its founding ideal of being open to all [Verification needed].

Start with the question of accuracy. Given that Wikipedia relies on its readers to spot and fix inaccuracies, errors are inevitable; entries may also have deliberate biases or inaccuracies introduced into them for political, personal or commercial motives. There have been several hoaxes. Britain's exam watchdog, Ofqual, warned in 2009 that Wikipedia was not “authoritative or accurate” and entries “may be completely untrue”. Studies suggest that Wikipedia may not be as accurate as specialist information sources, but compares well with the accuracy of books, newspapers and magazines. If you look up a subject you know about on Wikipedia, you will find that it mostly gets things right. Even Ofqual conceded that Wikipedia “can be an excellent starting point for research”. Its ability to provide a quick overview of a subject, with links to abundant references, is of immense value [Editorialising].

What of Wikipedia's sustainability? Over the past decade there have been occasional funding crunches as the site has grappled with its rapid growth. Yet a recently completed fundraising drive brought in $16m in donations in 50 days from 500,000 users. This suggests that Wikipedia has become more professional in its fundraising, and that crowdsourcing money, as well as content, is a viable model. The ubiquitous banner ads featuring Mr Wales annoyed some users [Attribution needed], but would probably be regarded by most as preferable to taking advertising or selling up to become part of an internet or media conglomerate, both of which might threaten Wikipedia's neutrality and its non-profit, volunteer-driven ethos.

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It is the third worry—that Wikipedia has become ossified and bureaucratic, discouraging new users from contributing—that is the greatest cause for concern. In recent years its most active contributors have become obsessed with obscure questions of doctrine and have developed their own curious jargon to describe the editing process. The number of regular contributors to Wikipedia's English edition peaked in March 2007 and has since declined by a third; the number of new contributors per month has fallen by half. Growth in the number of articles and edits has also levelled off. Mr Wales says all this is a sign of maturity: “The project is more complete—there's less to work on [Verification needed].” But insiders worry that new users perceive Wikipedia as “uninviting” and “insular”.

Wikipedia is already starting to look rather stiff and middle-aged. To ensure its long-term health, it needs to rediscover the flexibility of its early years.