Wikipedia, a free-content online encyclopedia written and maintained by a community of volunteers known as Wikipedians, began with its first edit on 15 January 2001, two days after the domain was registered. It grew out of Nupedia, a more structured free encyclopedia, as a way to allow easier and faster drafting of articles and translations.
A wiki is a form of online hypertext publication that is collaboratively edited and managed by its own audience directly through a web browser. A typical wiki contains multiple pages for the subjects or scope of the project, and could be either open to the public or limited to use within an organization for maintaining its internal knowledge base.
PlanetMath is a free, collaborative, mathematics online encyclopedia. The emphasis is on rigour, openness, pedagogy, real-time content, interlinked content, and also community of about 24,000 people with various maths interests. Intended to be comprehensive, the project is currently hosted by the University of Waterloo. The site is owned by a US-based nonprofit corporation, "PlanetMath.org, Ltd".
MediaWiki is free and open-source wiki software originally developed by Magnus Manske for use on Wikipedia on January 25, 2002, and further improved by Lee Daniel Crocker, after which it has been coordinated by the Wikimedia Foundation. It powers several wiki hosting websites across the Internet, as well as most websites hosted by the Foundation including Wikipedia, Wiktionary, Wikimedia Commons, Wikiquote, Meta-Wiki and Wikidata, which define a large part of the set requirements for the software. MediaWiki is written in the PHP programming language and stores all text content into a database. The software is optimized to efficiently handle large projects, which can have terabytes of content and hundreds of thousands of views per second. Because Wikipedia is one of the world's largest and most visited websites, achieving scalability through multiple layers of caching and database replication has been a major concern for developers. Another major aspect of MediaWiki is its internationalization; its interface is available in more than 400 languages. The software has more than 1,000 configuration settings and more than 1,800 extensions available for enabling various features to be added or changed. Besides its usage on Wikimedia sites, MediaWiki has been used as a knowledge management and content management system on websites such as Fandom, wikiHow and major internal installations like Intellipedia and Diplopedia.
The English Wikipedia is the primary English-language edition of Wikipedia, an online encyclopedia. It was created by Jimmy Wales and Larry Sanger on January 15, 2001, as Wikipedia's first edition.
Wikinews is a free-content news wiki and a project of the Wikimedia Foundation that works through collaborative journalism. Wikipedia co-founder Jimmy Wales has distinguished Wikinews from Wikipedia by saying, "On Wikinews, each story is to be written as a news story as opposed to an encyclopedia article." Wikinews's neutral point of view policy aims to distinguish it from other citizen journalism efforts such as Indymedia and OhmyNews. In contrast to most Wikimedia Foundation projects, Wikinews allows original work in the form of original reporting and interviews. In contrast to newspapers, Wikinews does not permit op-ed.
The German Wikipedia is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia.
The Wikimedia movement is the global community of contributors to the Wikimedia projects, including Wikipedia. This community directly builds and administers these projects with the commitment of achieving this using open standards and software.
Baidu Baike is a semi-regulated Chinese-language collaborative online encyclopedia owned by the Chinese technology company Baidu. The beta version was launched on April 20, 2006, and the official version was launched on April 21, 2008, edited by registered users. As of February 2022, it has 25.54 million entries and more than 7.5 million editors. It has the largest number of entries in the world of any Chinese-language online encyclopedia.
The Encyclopedia of Earth is an electronic reference about the Earth, its natural environments, and their interaction with society. The Encyclopedia is described as a free, fully searchable collection of articles written by scholars, professionals, educators, and other approved experts, who collaborate and review each other's work. The articles are written in non-technical language and are intended to be useful to students, educators, scholars, and professionals, as well as to the general public. The authors, editors, and even copy editors are attributed on the articles with links to biographical pages on those individuals.
Wikipedia is a free-content online encyclopedia, written and maintained by a community of volunteers, collectively known as Wikipedians, through open collaboration and the use of wiki-based editing system MediaWiki. Wikipedia is the largest and most-read reference work in history. It consistently ranks as one of the 10 most popular websites in the world, and as of 2024 it is ranked the 5th most visited website on the Internet by Semrush. Founded by Jimmy Wales and Larry Sanger, on January 15, 2001, it is hosted by the Wikimedia Foundation, an American nonprofit organization that employed a staff of over 700 people by October 2023.
Citizendium is an English-language wiki-based free online encyclopedia launched by Larry Sanger, co-founder of Nupedia and Wikipedia.
Uncyclopedia is several forks of satirical online encyclopedias that parody Wikipedia. Its logo, a hollow "puzzle potato", parodies Wikipedia's globe puzzle logo, and it styles itself as "the content-free encyclopedia", parodying Wikipedia's slogan of "the free encyclopedia". Founded in 2005 as an English-language wiki, the project spans more than 75 languages as well as several subprojects parodying other wikis. Uncyclopedia's name is a portmanteau of the prefix un- and the word encyclopedia.
Radiopaedia is a wiki-based international collaborative educational web resource containing a radiology encyclopedia and imaging case repository. It is currently the largest freely available radiology related resource in the world with more than 50,000 patient cases and over 16,000 reference articles on radiology-related topics. The open edit nature of articles allows radiologists, radiology trainees, radiographers, sonographers, and other healthcare professionals interested in medical imaging to refine most content through time. An editorial board peer reviews all contributions.
WikiTrust was a software product, available as a Firefox Plugin, which aimed to assist editors in detecting vandalism and dubious edits by highlighting the "untrustworthy" text with a yellow or orange background. As of September 2017, the server is offline, but the code is still available for download.
Nupedia was an English-language online encyclopedia whose articles were written by volunteer contributors with appropriate subject matter expertise, reviewed by expert editors before publication, and licensed as free content. It was founded by Jimmy Wales and underwritten by Bomis, with Larry Sanger as editor-in-chief. Nupedia operated from October 1999 until September 2003. It is best known today as the predecessor of Wikipedia. Nupedia had a seven-step approval process to control content of articles before being posted, rather than live wiki-based updating. Nupedia was designed by a committee of experts who predefined the rules. It had only 21 articles in its first year, compared with Wikipedia having 200 articles in the first month, and 18,000 in the first year.
The following outline is provided as an overview of and a topical guide to Wikipedia:
PlanetPhysics was a virtual community with several Internet sites supported by a non-profit organization registered in the USA in an open science, open data, peer-to-peer review mode that aimed to help make physics, and related mathematics, knowledge much more accessible, as well as to further develop physical, logical, computational and mathematical physics concepts.
Gender bias on Wikipedia is a term used to describe various sex-related facts about Wikipedia: its volunteer contributors are mostly male, although almost 400,000 encyclopedic biographies about women exist on Wikipedia men have many more, and topics primarily of interest to women are less well-covered.
