All Wikimedia projects are developed collaboratively by their users on a wiki. A wiki is a system of managing the content of a website allowing everybody to edit all pages, using the Mediawiki software. The content of Wikimedia projects is free as per the Creative Commons - Attribution - Share alike licence, which means that it can be edited, copied and distributed freely, without paying any royalties, provided that the terms of the licence are respected.
Wikipedia is the best known Wikimedia project. It aims at building a free online encyclopedia in all languages of the world, to which everybody can contribute. The project started in January 2001 in English, and a few months later the French version was created. Today Wikipedia is available in more than 300 languages and has over 25 millions articles in all languages. The English version has more than 4 million articles while the French version has a little bit more than 1.4 million. Since the beginning of the project, more than 100,000 users have completed at least ten edits.