MediaWiki - Used by tens of thousands of websites and thousands of companies and organizations. It powers Wikipedia as well

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Meta-Wiki - The global community site for the Wikimedia Foundation's projects and related projects, from coordination and documentation to planning and analysis

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Wikibooks - Open-content textbooks collection that anyone can edit

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Wikidata - The free knowledge base with almost 90 million data items that anyone can edit

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Wikimedia Commons - A collection of 64,133,442 freely usable media files to which anyone can contribute

Visit Wikimedia Commons - A collection of nearly 65 million freely usable media files to which anyone can contribute

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