Differences between Wikipedia, Wikimedia, MediaWiki, and wiki/es

¿Confundido sobre la diferencia entre MediaWiki, Wikimedia, Wikipedia y Wiki?

Wiki
Wiki is a generic term which is used to describe a certain kind of collaborative website that can be edited by any user and/or visitor; it is not a proper noun.
 * wiki (as an adjective), "the wiki way", and the antonym un-wiki are also used to describe the community-oriented philosophy that goes with such a system (e.g. "that's not a very wiki way of doing things").
 * Wiki (with a capital 'W') is an incorrect term, although it has sometimes been used to refer to either Wikipedia or the Portland Pattern Repository (also known as WikiWikiWeb), which was the first wiki to be created.
 * wiki software and wiki engine are terms referring to pieces of software that power wiki-based websites. There are many different types of wiki software; some very simple, others with advanced features. See also: Wikipedia's entry on "wiki software".

For a more complete description, see Wikipedia's entry on "wiki".

Wikimedia
Wikimedia is the collective name for the Wikimedia movement, revolving around a group of inter-related projects, including Wikipedia, Wiktionary, Wikiquote and others, which aim to use the collaborative power of the Internet, and the wiki concept, to create and share free knowledge of all kinds.

Wikimedia is also the short name for the Wikimedia Foundation, a non-profit organization headquartered in San Francisco that runs these projects.
 * El término servidores de Wikimedia es usado a veces para referirse al hardware informático en el que están hospedados todos los proyectos de Wikimedia. Los servidores son mantenidos principalmente por voluntarios, muchos de los cuales también trabajan en el desarrollo del software MediaWiki (ver más abajo).
 * Wikimedia Deutschland, Wikimedia Russia etc. no son parte de la Fundación Wikimedia, pero son usualmente organizaciones amigas.
 * El Meta-Wiki de Wikimedia, mejor conocido como Meta, es el wiki utilizado para discutir asuntos que afectan a todos los proyectos de Wikimedia. Véase también: Meta:Acerca de (en inglés).
 * Meta-Wiki no debería confundirse con MetaWiki, un motor de búsqueda que no pertenece a Wikimedia.

Wikipedia
Wikipedia is a Wikimedia project that is a global, free and multilingual internet encyclopedia. It is the oldest, and largest, Wikimedia project, predating the Wikimedia Foundation itself. Wikipedia is a wiki that runs on MediaWiki.

MediaWiki
MediaWiki is a particular wiki engine, that is developed for and used by Wikipedia and the other Wikimedia projects. MediaWiki is freely available for others to use (and improve), and it is in use by all sorts of projects around the world.

Véase también: MediaWiki, Sitios que utilizan MediaWiki.

Vídeo

 * [//www.youtube.com/watch?v=gXD1TRGafQ0 The State of Wikipedia] en YouTube