Wikipedia

Wikipedia is a free online encyclopedia that aims to document human knowledge in a collaborative, openly editable format. It is produced by volunteers and operated by the Wikimedia Foundation, a non-profit organization based in the United States. Wikipedia is available in many languages, with the English edition having the largest number of articles and readers.

History and development: Wikipedia was launched in 2001 by Jimmy Wales and Larry Sanger as a complementary project to the traditional, expert-written Nupedia. The open editing model allowed anyone to contribute, review, and correct content. Over time, Wikipedia became the core project of the Wikimedia Foundation, while Nupedia was retired.

Content and licensing: All content on Wikipedia is free to reuse under a permissive license, currently Creative Commons Attribution-ShareAlike (CC BY-SA) 3.0 or later. It was originally released under the GNU Free Documentation License (GFDL) and transitioned to CC BY-SA in the late 2000s. This licensing enables broad reuse and redistribution with attribution and share-alike requirements.

Policies and editing: Wikipedia operates under guidelines such as neutral point of view, verifiability, and no original research. Editors use references to reliable sources and engage in discussions on article talk pages to resolve disputes. The platform employs page histories, vandalism controls, and community review to maintain quality, though article reliability can vary by topic and contributor activity.

Structure and access: The encyclopedia is freely accessible online and exists in hundreds of languages. The English edition is the largest, and many topics also appear across other language editions. The site links to a network of sister projects that host images, data, and educational resources.

Impact and reception: Wikipedia has become a widely used starting point for information, research, and learning. It faces ongoing critiques related to accuracy, systemic bias, and the need for careful sourcing and critical evaluation.