Wikimedia Commons

The Wikimedia Commons (also called "Wikicommons") is a repository of free content images, sound and other multimedia files. Like Wikipedia, it is a project of the Wikimedia Foundation. It provides a common resource repository to all the various Wikimedia sister projects in any language.

The files uploaded to the Commons repository can be used like locally uploaded files on all other projects on the Wikimedia servers in all languages, including Wikipedia, Wikibooks, Wikisource and Wikinews, or downloaded for offsite use, as all of the content is either in the public domain or released under free licenses such as the GNU Free Documentation License.

On 24 May 2005, Wikimedia Commons reached a milestone of 100,000 uploaded media files (excluding thousands of weather and market data images for Wikinews). It also received an honorary mention at the 2005 Prix Ars Electronica awards in May 2005.

Media on Commons which is tagged with decimal coordinates has a Geo microformat on its page there.

Policies and usage
Most Wikimedia projects still allow local uploads which are not visible to other projects or languages, but this option is meant to be used primarily for material which local project policies allow, but which would not be permitted according to the copyright policy of the Commons, such as fair use content. Wikimedia Commons itself does not allow fair use or uploads under non-free licenses, including licenses which restrict commercial use of materials or disallow derivative works. Licenses that are acceptable include the GNU Free Documentation License, Creative Commons Attribution and ShareAlike licenses, and the public domain.

Given its primary function as a supporting project for the other Wikimedia web sites, the main content policy for files uploaded to the Commons is that they must be potentially useful on any of the Wikimedia projects. This excludes material such as purely personal pictures and artwork, in contrast to image sharing repositories like Flickr, Facebook and DeviantART. Nevertheless, large numbers of files hosted on the Commons are not used directly on any Wikimedia project and likely never will be; as such, the project has grown into a repository of multimedia in its own right, which is frequently linked to from articles on Wikipedia and other Wikimedia websites to provide supplemental materials.

The default language for the Commons is English, but registered users can customize their interface to use any other available user interface translations. Many content pages, in particular policy pages and portals, have also been translated into various languages. Files on the Wikimedia Commons are categorized using MediaWiki's category system. In addition, they are often collected on individual topical gallery pages. While the project was originally proposed to also contain free text files, these continue to be hosted on a sister project, Wikisource.