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Wikipedia (i// or i// WIK-i-PEE-dee-ə) is a multilingual, web-based, free-content encyclopedia project supported by the Wikimedia Foundation and based on an openly editable model. The name "Wikipedia" is a portmanteau of the words wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning "quick") and encyclopedia. Wikipedia's articles provide links designed to guide the user to related pages with additional information.
Wikipedia is written collaboratively by largely anonymous Internet volunteers who write without pay. Anyone with Internet access can write and make changes to Wikipedia articles, except in limited cases where editing is restricted to prevent disruption or vandalism. Users can contribute anonymously, under a pseudonym, or, if they choose to, with their real identity.
The fundamental principles by which Wikipedia operates are the five pillars. The Wikipedia community has developed many policies and guidelines to improve the encyclopedia; however, it is not a formal requirement to be familiar with them before contributing.
Since its creation in 2001, Wikipedia has grown rapidly into one of the largest reference websites, attracting 470 million unique visitors monthly as of February 2012. There are more than working on more than 31,000,000 articles in 285 languages. As of today, there are 4,620,840 articles in English. Every day, hundreds of thousands of visitors from around the world collectively make tens of thousands of edits and create thousands of new articles to augment the knowledge held by the Wikipedia encyclopedia. (See the statistics page for more information.)
People of all ages, cultures and backgrounds can add or edit article prose, references, images and other media here. What is contributed is more important than the expertise or qualifications of the contributor. What will remain depends upon whether the content is free of copyright restrictions and contentious material about living people, and whether it fits within Wikipedia's policies, including being verifiable against a published reliable source, thereby excluding editors' opinions and beliefs and unreviewed research. Contributions cannot damage Wikipedia because the software allows easy reversal of mistakes and many experienced editors are watching to help ensure that edits are cumulative improvements. Begin by simply clicking the Edit link at the top of any editable page!
Wikipedia is a live collaboration differing from paper-based reference sources in important ways. Unlike printed encyclopedias, Wikipedia is continually created and updated, with articles on historic events appearing within minutes, rather than months or years. Older articles tend to be more comprehensive and balanced; newer articles may contain misinformation and/or unencyclopedic content. Any article may contain undetected vandalism. Awareness of this helps the reader to obtain valid information and avoid recently added misinformation (see Wikipedia:Researching with Wikipedia).
What Wikipedia is not explains Wikipedia's scope. More information on key topics appears hereafter. Further advice is at Wikipedia:FAQ, Wikipedia:Advice for parents, and Wikipedia:Questions. Wikipedia:General disclaimer warns you about Wikipedia's limitations. For help getting started with editing or other issues, see Help:Contents.
Wikipedia was founded as an offshoot of Nupedia, a now-abandoned project to produce a free encyclopedia. Nupedia had an elaborate system of peer review and required highly qualified contributors, but the writing of articles was slow. During 2000, Jimmy Wales, founder of Nupedia, and Larry Sanger, whom Wales had employed to work on the project, discussed ways of supplementing Nupedia with a more open, complementary project. Multiple sources suggested that a wiki might allow members of the public to contribute material, and Nupedia's first wiki went online on January 10, 2001.
There was considerable resistance on the part of Nupedia's editors and reviewers to the idea of associating Nupedia with a website in the wiki format, so the new project was given the name "Wikipedia" and launched on its own domain, wikipedia.com, on January 15 (now called "Wikipedia Day" by some users). The bandwidth and server (in San Diego) were donated by Wales. Other current and past Bomis employees who have worked on the project include Tim Shell, one of the cofounders of Bomis and its current CEO, and programmer Jason Richey. The domain was eventually changed to the present wikipedia.org when the not-for-profit Wikimedia Foundation was launched as its new parent organization, with the ".org" top-level domain denoting its non-commercial nature.
In May 2001, a large number of non-English Wikipedias were launched—in Catalan, Chinese, Dutch, Esperanto, French, German, Hebrew, Italian, Japanese, Portuguese, Russian, Spanish, and Swedish. These were soon joined by Arabic and Hungarian. In September, Polish was added, and further commitment to the multilingual provision of Wikipedia was made. At the end of the year, Afrikaans, Norwegian, and Serbo-Croatian versions were announced.
Anyone with Web access can edit Wikipedia, and this openness encourages inclusion of a tremendous amount of content. About 77,000 editors—from expert scholars to casual readers—regularly edit Wikipedia, and these experienced editors often help to create a consistent style throughout the encyclopedia, following our Manual of Style.
Several mechanisms are in place to help Wikipedia members carry out the important work of crafting a high-quality resource while maintaining civility. Editors are able to watch pages and techies can write editing programs to keep track of or rectify bad edits. Where there are disagreements on how to present facts, editors work together to arrive at an article that fairly represents current expert opinion on the subject.
Although the Wikimedia Foundation owns the site, it is largely uninvolved in writing and daily operations.
Most of Wikipedia's text and many of its images are dual-licensed under the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA) and the GNU Free Documentation License (GFDL) (unversioned, with no invariant sections, front-cover texts, or back-cover texts). Some text has been imported only under CC-BY-SA and CC-BY-SA-compatible license and cannot be reused under GFDL; such text is identified either on the page footer, in the page history or on the discussion page of the article that utilizes the text. Every image has a description page which indicates the license under which it is released or, if it is non-free, the rationale under which it is used.
Contributions remain the property of their creators, while the CC-BY-SA and GFDL licenses ensure the content is freely distributable and reproducible. (See the copyright notice and the content disclaimer for more information.)
Text on Wikipedia is a collaborative work, and the efforts of individual contributors to a page are recorded in that page's history, which is publicly viewable. Information on the authorship of images and other media, such as sound files, can be found by clicking on the image itself or the nearby information icon to display the file page, which includes the author and source, where appropriate, along with other information.
Many visitors come to Wikipedia to acquire knowledge, while others come to share knowledge. At this very instant, dozens of articles are being improved, and new articles are also being created. Changes can be viewed at the Recent changes page and a random page at random articles. Over 3,500 articles have been designated by the Wikipedia community as featured articles, exemplifying the best articles in the encyclopedia. Another 15,000 articles are designated as good articles. Some information on Wikipedia is organized into lists; the best of these are designated as featured lists. Wikipedia also has portals, which organize content around topic areas; our best portals are selected as featured portals. Articles can be found using the search box on the top-right side of the screen.
Wikipedia is available in languages other than English. Wikipedia has more than two hundred and eighty languages, including a Simple English version, and related projects include a dictionary, quotations, books, manuals, and scientific reference sources, and a news service (see sister projects). All of these are maintained, updated, and managed by separate communities, and often include information and articles that can be hard to find through other common sources.
Wikipedia articles are all linked, or cross-referenced. When highlighted text like this is seen, it means there is a link to some relevant article or Wikipedia page with further in-depth information. Holding the mouse over the link will often show to where the link will lead. The reader is always one click away from more information on any point that has a link attached. There are other links towards the ends of most articles, for other articles of interest, relevant external websites and pages, reference material, and organized categories of knowledge which can be searched and traversed in a loose hierarchy for more information. Some articles may also have links to dictionary definitions, audio-book readings, quotations, the same article in other languages, and further information available on our sister projects. Additional links can be easily made if a relevant link is missing—this is one simple way to contribute.
As wiki documents, articles are never considered complete and may be continually edited and improved. Over time, this generally results in an upward trend of quality and a growing consensus over a neutral representation of information.
Users should be aware that not all articles are of encyclopedic quality from the start: they may contain false or debatable information. Indeed, many articles start their lives as displaying a single viewpoint; and, after a long process of discussion, debate, and argument, they gradually take on a neutral point of view reached through consensus. Others may, for a while, become caught up in a heavily unbalanced viewpoint which can take some time—months perhaps—to achieve better balanced coverage of their subject. In part, this is because editors often contribute content in which they have a particular interest and do not attempt to make each article that they edit comprehensive. However, eventually, additional editors expand and contribute to articles and strive to achieve balance and comprehensive coverage. In addition, Wikipedia operates a number of internal resolution processes that can assist when editors disagree on content and approach. Usually, editors eventually reach a consensus on ways to improve the article.
The ideal Wikipedia article is well written, balanced, neutral, and encyclopedic, containing comprehensive, notable, verifiable knowledge. An increasing number of articles reach this standard over time, and many already have. Our best articles are called Featured Articles (and display a small star in the upper right corner of the article), and our second best tier of articles are designated Good Articles. However, this is a process and can take months or years to be achieved, as each user adds their contribution in turn. Some articles contain statements which have not yet been fully cited. Others will later be augmented with new sections. Some information will be considered by later contributors to be insufficiently founded and, therefore, may be removed.
While the overall trend is toward improvement, it is important to use Wikipedia carefully if it is intended to be used as a research source, since individual articles will, by their nature, vary in quality and maturity. Guidelines and information pages are available to help users and researchers do this effectively, as is an article that summarizes third-party studies and assessments of the reliability of Wikipedia.
Wikipedia has advantages over traditional paper encyclopedias. Wikipedia has a very low "publishing" cost for adding or expanding entries and a low environmental impact in some respects, since it never needs to be printed, although computers have their own environmental cost. In addition, Wikipedia has wikilinks instead of in-line explanations and it incorporates overview summaries (article introductions) with the extensive detail of full articles. Additionally, the editorial cycle is short. A paper encyclopedia stays the same until the next edition, whereas editors can update Wikipedia at any instant, around the clock, to help ensure that articles stay abreast of the most recent events and scholarship.
Wikipedia's greatest strengths, weaknesses, and differences all arise because it is open to anyone, it has a large contributor base, and its articles are written by consensus, according to editorial guidelines and policies.
The MediaWiki software that runs Wikipedia retains a history of all edits and changes, thus information added to Wikipedia never "vanishes". Discussion pages are an important resource on contentious topics. Therefore, serious researchers can often find a wide range of vigorously or thoughtfully advocated viewpoints not present in the consensus article. As with any source, information should be checked. A 2005 editorial by a BBC technology writer comments that these debates are probably symptomatic of cultural changes that are happening across all sources of information (including search engines and the media), and may lead to "a better sense of how to evaluate information sources".
Wikipedia disclaimers apply to all pages on Wikipedia. However, the consensus in Wikipedia is to put all disclaimers only as links and at the end of each article. Proposals to have a warning box at the beginning have been rejected. Some do not like the way it looks or that it calls attention to possible errors in Wikipedia.
Wikipedia, in common with many websites, has a disclaimer that, at times, has led to commentators citing these in order to support a view that Wikipedia is unreliable. A selection of similar disclaimers from places which are often regarded as reliable (including sources such as Encyclopædia Britannica, Associated Press, and the Oxford English Dictionary) can be read and compared at Wikipedia:Non-Wikipedia disclaimers. Wikipedia content advisories can also be found here.
Anyone can contribute to Wikipedia by clicking on the Edit tab in an article. Before beginning to contribute, however, read some handy helping tools such as the tutorial and the policies and guidelines, as well as our welcome page. offers many benefits. It is important to realize that in contributing to Wikipedia, users are expected to be civil and neutral, respecting all points of view, and only add verifiable and factual information rather than personal views and opinions. "The five pillars of Wikipedia" cover this approach and are recommended reading before editing. (Vandals are reported via the Administrator Notice Board and may be temporarily blocked from editing Wikipedia.)
Most articles start as stubs, but after many contributions, they can become featured articles. Once the contributor has decided a topic of interest, they may want to request that the article be written (or they could research the issue and write it themselves). Wikipedia has on-going projects, focused on specific topic areas or tasks, which help coordinate editing.
The ease of editing Wikipedia results in many people editing. That makes the updating of the encyclopedia very quick, almost as fast as news websites.
Wikipedia uses a simple yet powerful page layout to allow editors to concentrate on adding material rather than page design. Page aspects facilitated include:
Page editing is accessed through tabs that are found along the top edge of the page. These are:
Wikipedia has robust version and reversion controls. This means that poor-quality edits or vandalism can quickly and easily be reversed or brought up to an appropriate standard by any other editor, so inexperienced editors cannot accidentally do permanent harm if they make a mistake in their editing. As there are many more editors intent on improving articles than not, error-ridden articles are usually corrected promptly.
Wikipedia content is intended to be factual, notable, verifiable with cited external sources, and neutrally presented.
The appropriate policies and guidelines for these are found at:
The Wikipedia community is largely self-organising, so that anyone may build a reputation as a competent editor and become involved in any role s/he may choose, subject to peer approval. Individuals often will choose to become involved in specialised tasks, such as reviewing articles at others' request, watching current edits for vandalism, watching newly created articles for quality control purposes, or similar roles. Editors who believe they can serve the community better by taking on additional administrative responsibility may ask their peers for agreement to undertake such responsibilities. This structure enforces meritocracy and communal standards of editorship and conduct. At present a minimum approval of 75–80% from the community is required to take on these additional tools and responsibilities. This standard tends to ensure a high level of experience, trust, and familiarity across a broad front of aspects within Wikipedia.
A variety of software-assisted systems and automated programs help editors and administrators to watch for problematic edits and editors. Theoretically all editors and users are treated equally with no "power structure". There is, however, a hierarchy of permissions and positions, some of which are listed hereafter:
Wikipedia has a rich set of methods to handle most abuses that commonly arise. These methods are well-tested and should be relied upon.
As well as systems to catch and control substandard and vandalistic edits, Wikipedia also has a full style and content manual and a variety of positive systems for continual article review and improvement. Examples of the processes include peer review, good article assessment, and the featured article process, a rigorous review of articles that are intended to meet the highest standards and showcase Wikipedia's capability to produce high-quality work.
In addition, specific types of article or fields often have their own specialized and comprehensive projects, assessment processes (such as biographical article assessment), and expert reviewers within specific subjects. Nominated articles are also frequently the subject of specific focus on the neutral point of view noticeboard or in WikiProject Cleanup.
Wikipedia uses MediaWiki software, the open-source program used not only on Wikimedia projects but also on many other third-party websites. The hardware supporting the Wikimedia projects is based on several hundred servers in various hosting centers around the world. Full descriptions of these servers and their roles are available on this Meta-Wiki page. For technical information about Wikipedia, check Technical FAQ. Wikipedia publishes various types of metadata; and, across its pages, are many thousands of microformats.
Wikipedia is run as a communal effort. It is a community project whose result is an encyclopedia. Feedback about content should, in the first instance, be raised on the discussion pages of those articles. Be bold and edit the pages to add information or correct mistakes.
The Help:Contents may be accessed by clicking help displayed under the ► Interaction tab at the top left of all pages.
There is an established escalation-and-dispute process within Wikipedia, as well as pages designed for questions, feedback, suggestions, and comments. For a full listing of the services and assistance that can be requested on Wikipedia, see Wikipedia:Requests.
Facilities to help users researching specific topics can be found at:
Because of the nature of Wikipedia, it is encouraged that people looking for information should try to find it themselves in the first instance. If, however, information is found to be missing from Wikipedia, be bold and add it so others can gain.
For specific discussion not related to article content or editor conduct, see the Village pump, which covers such subjects as announcements, policy and technical discussion, and information on other specialized portals such as the help, reference and peer review desks. The Community Portal is a centralized place to find things to do, collaborations, and general editing help information, and find out what is happening. The Signpost, a community-edited newspaper, has recent news regarding Wikipedia, its sister projects, and the Wikimedia Foundation.
To contact individual contributors, leave a message on their talk page. Standard places to ask policy and project-related questions are the Village Pump, online, and the Wikipedia mailing-lists, over e-mail. Reach other Wikipedians via IRC and e-mail.
In addition, the Wikimedia Foundation Meta-Wiki is a site for coordinating the various Wikipedia projects and sister projects (and abstract discussions of policy and direction). Also available are places for submitting bug reports and feature requests.
For a full list of contact options, see Wikipedia:Contact us.
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