Wikipedia is a free encyclopedia, collaboratively being constructed at the web site

using the Wiki metaphor.

There are four main differences between Wikipedia and E2:


  • Nobody owns a node; (almost) everything can be edited by anybody, even without logging in.
  • A central page lists all Recent Changes; complete histories of all articles are kept indefinitely and can be accessed by anybody, so that changes can be reviewed and easily undone if necessary.
  • No voting or ranking occurs.
  • No editors exist, or rather: anybody can be an editor.
  • Every contributor licenses their articles under the copyleft GNU Free Documentation License which ensures that the material will stay free forever. If the website goes down (or if not), somebody else can take the data and start over.
Subject matter:
  • The goal of Wikipedia is to build an encyclopedia; as such, personal opinions, jokes, diaries, dictionary definitions, literature and poetry are not included.
  • All articles have an associated "Talk" page where discussion aimed at improving the article can take place.
  • Controversial topics are (ideally) covered from a "Neutral Point of View" (NPOV), a characterization of the debate that people on all sides can accept as "fair". In practice, articles about controversial topics are frequently subject of "edit wars" and should always be read in conjunction with their "Talk" and "History" pages.
  • Articles are written in Wiki markup (without CamelCase) rather than in HTML; this includes a special markup for tables.
  • Mathematical formulas can be constructed in TeX.
  • Links to not-yet-existing articles are presented differently from ordinary links. A user option allows yet another presentation for links to short "stub" articles that may need more work.
  • Links to external web sites are possible, and images, movies and sound files may be uploaded.
  • Wikipedia does not have softlinks.
  • All articles that have a link to the current article can be listed ("What links here").
  • There is a hierarchy of categories: every category can have several sub- and super-categories, and every article can be placed into several categories. Every article lists the categories it belongs to at the bottom, and the articles belonging to a given category can be listed together. Anybody can create or change categories.
  • Users can keep track of changes to their favorite articles with a watchlist feature.
  • A template feature allows the easy inclusion of uniformly formatted content into several articles; templates can take arguments and are for example used for the "taxoboxes" of biological organisms. Anybody can create or change templates.
  • All articles are indexed by Google. (This is now also true for E2.)
  • Full-text boolean search is possible, but often disabled and replaced by Google search for performance reasons.
  • There is no chatterbox feature, only an irc channel: #Wikipedia on
  • Messaging is done by editing the discussion section of other user's home pages.
  • The whole database can be downloaded in various formats.
  • An internal weekly newspaper, the Wikipedia Signpost, keeps users informed about project-wide developments.


The project was started in January 2001 by Larry Sanger, a philosophy Ph.D., and Jimbo Wales, an internet entrepreneur. Initially it was intended as a companion for Nupedia, a slow-moving peer-reviewed copyleft encyclopedia which has since all but died. Wales provided the bandwidth and server and, until February 1, 2002, employed Sanger as coordinator of Nupedia and Wikipedia.

The most important early actions by Sanger were the formulation and enforcement of the NPOV policy, setting up the site's general link structure, and the weeding out of non-encyclopedic materials. Jimbo Wales initially remained in the background.

In 2001, RMS endorsed Wikipedia as the embodiment of GNUpedia, a project of constructing a free encyclopedia and learning resource which he had envisioned earlier.

Many hundred writers contribute on a regular basis. Some thirty active sister projects in other languages have been created, the most active being the German, Japanese, French, Dutch, Polish, Swedish, Spanish, Chinese and Esperanto Wikipedias. These are not mere translations, but encyclopedias in their own right.

Occasionally, obnoxious users ("vandals") have to be banned from the site. This happens after extensive debate on the project's mailing lists, which also serve to formulate policy and coordinate the technical development. Jimbo Wales has the position of a benevolent dictator, a philosopher king of sorts. In 2004, an Arbitration Committee was formed, which led to a reduction of Wales' involvement in banning decisions.

When the project was initially started, Wales had some plans of recovering his investments in the distant future. Occasionally the specter of banner ads has been raised. This prospect led to a fork of the very active Spanish Wikipedia in February 2002; the forked version is called "Enciclopedia Libre" and is hosted at the University of Sevilla.

Jimbo Wales has now repeatedly stated that Wikipedia is his hobby, that he does not intend to make or recover any money from it, and that he opposes advertising on the site. In August 2002, the main URL for the site was changed from to Plans to create a non-profit organization to further develop Wikipedia had been voiced repeatedly. In June 2003, Wales announced that he had created the Florida-registered non-profit Wikimedia Foundation, Inc. and transferred several of his copyrights to it. The foundation began accepting donations via PayPal (as user in August 2003. In December 2003, Wales put out a call for donations to purchase backup hardware; some two days after the request for $20,000 had been posted on Slashdot and Kuro5hin, the money was collected. The foundation has since run regular fund raising drives.

The Wikipedia content is being used by several dozen other sites, some of which achieving higher Google Pageranks than Wikipedia itself. Most of these cannot be called forks, as they simply download and present the unmodified data. However, in addition to the fork of the Spanish version mentioned above, there is one genuine fork of Wikipedia: it's called Wikinfo (formerly internet-encyclopedia) and run by Fred Bauder. Wikinfo allows biased treatments and does not follow the NPOV policy. Then there's Uncyclopedia, a wiki-based parody on Wikipedia.

According to Alexa, in Summer 2005 Wikipedia ranked worldwide among the 60 highest-traffic websites; it received about as much traffic (roughly 1500 hits per second) as The Internet Movie Database or, more than the New York Times,, or

As of August 2005, Wikipedia contained more than 700,000 genuine encyclopedia articles. Some of these were produced automatically, including about 30,000 about US counties and cities generated from census data.

Wikipedia is now by far the largest Wiki in existence and may very well be the largest collaborative project in the history of humanity. It has been the subject of coverage in the New York Times, the New York Times Magazine, Wired, and MIT's Technology Review. In May 2004, Wikipedia won the Webby Award in the category "Community". In October 2004, the German computer magazine c't performed a comparison of the quality of 63 blindly chosen articles of three encyclopedias: German Wikipedia, Brockhaus and German Microsoft Encarta; Wikipedia won.

In late 2005, Wikipedia entered the news in a major way. The John Seigenthaler affair involved a libelous statement added by an anonymous user to the article about journalist John Seigenthaler. The statement went unchallenged for several months, until Seigenthaler wrote a widely distributed USA Today editorial in which he complained about Wikipedia's lack of accountability. Shortly thereafter, it was revealed that Adam Curry had edited Wikipedia in order to amplify his role in the development of podcasting and Jimbo Wales had edited the article about himself in order to downplay the role of Larry Sanger in the early development of Wikipedia. At about the same time, a Nature study found that the average Wikipedia science article contains about 4 inaccuracies, compared to 3 in the average Encyclopædia Britannica science article. Subsequent editorials in Nature and Scientific American generally endorsed Wikipedia and asked all scientists to contribute. Finally, in early 2006 it was revealed that several staffers of U.S. Congressmen had engaged in misleading or malicious editing of Wikipedia articles about politicians.

As a result of all the media coverage, Wikipedia was propelled to rank 18 of the Alexa website list. By 2008 it had reached rank 8, surpassed only by search engines and social networking sites.

The first international Wikipedia conference, Wikimania, was held in August 2005 in Frankfurt am Main, Germany. Jimbo Wales, Ward Cunningham (the inventor of wikis) and RMS gave keynote addresses. The next Wikimania conference was held in the summer of 2006 at Harvard University in Boston, followed by one in Taipei, Taiwan in 2007 and one in Alexandria, Egypt in 2008. The 2009 Wikimania is scheduled to take place in Buenos Aires, Argentina.

Software and Technology

In January 2002, the website (then located in San Diego) switched from the perl-based Usemod wiki software that used a flat text database to a custom PHP system on top of a MySQL database, mainly written by Magnus Manske. This allowed to implement many new features but initially led to some site slowdowns as problems were ironed out. The software was again rewritten from scratch in July 2002 by Lee Daniel Crocker; it is now known as MediaWiki.

In 2002, a new server was purchased (2-CPU Athlon MP-1700+ with 2GB RAM running RedHat Linux and apache); performance improved but the site still intermittently slowed to a crawl. In May 2003, a second server was acquired, thus allowing to run the database and the web server on different machines. This server had some hardware problems however. Brion Vibber has since emerged as the technical leader who updates the software and manages the servers.

After the Wikimedia Foundation successfully raised money in late 2003, nine new servers were purchased in February 2004; they were installed in Florida and Vibber planned to employ them in a doubly redundant scheme using several squid proxy caching servers.

In Spring 2004, the above-mentioned category system was installed, and the site's user interface was redesigned, resulting in considerably less clutter.

As of Summer 2005, the Wikimedia projects were using 83 servers (67 machines in Florida, 5 near Paris, and 11 in Amsterdam), almost all running Linux. These included 7 database servers, 49 Apache web servers and 14 squid proxy cache servers. Brion Vibber is now a full-time employee of the Wikimedia Foundation.

Related projects

The Wikimedia Foundation now runs several other projects in addition to Wikipedia, all having to do with the free dissemination of wiki-developed information and all using the MediaWiki software:
  • Wiktionary, a dictionary whose goal is to describe all words of all languages
  • Wikicommons, a depository of free photos and other media, to be used by Wikimedia projects and others
  • Wikibooks, textbooks written wiki-style
  • Wikinews, a site with current news articles
  • Wikiquote, a collection of quotes
  • Wikisource, a collection of free source materials, such as public domain poems or books

Related links

This writeup is in the public domain.

As a slight addendum to the above, several things have changed since 2002 for the Wikimedia Foundation (WMF). Possibly the most relevant is that there are now a few more sister projects. In addition to background wikis which are of little interest to the general public (e.g. Meta-Wiki, which is discussion of the WMF projects themselves and MediaWiki, which develops the software that runs all of the other projects), there are:

  • Wikispecies: a taxonomic directory of species. This is mostly populated by specialists but everyone can add something to the project.
  • Wikiversity: spun off from Wikibooks, this is for more general learning resources than a strict textbook. E.g. there is a bloom clock that has been gathering data about when certain species of flower bloom around the world. Wikiversity encourages original research, unlike Wikipedia.
  • Wikidata: structured database. Part of the reason for creating it was to synchronize some basic data (e.g. dates of birth) across the 275 or so language editions of Wikipedia but it also got a huge boost from inheriting Google's Freebase and has millions of data items. Due to a particularity of licensing for databases, it is the only project whose contributions are in the public domain by default. Also, its interface is JavaScript heavy and you don't interact directly with pages but edit database entries instead.
  • Wikivoyage: a free travel guide. Like Lonely Planet but updated in real time by travelers all over the globe. This appears to be the newest project but it was actually adopted by the WMF in 2013 after having been a fork of Wikitravel, which was founded in 2003 by some Wikipedians who wanted to make a more reliable and up-to-date travel guide.

All noders are invited to participate in all projects—you all have something to give.

As a post-script, I would be remiss if I didn't mention the only retired WMF project: 9/11 Memories. This was made shortly after the September 11th attacks and was a kind of discussion board, memorial, and general dumping ground of public memory about 9/11. It was closed after a couple of years and was eventually removed from almost all references. Never forget.

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