There are many reusers of Wikipedia's content, and more are welcome. If you want to use Wikipedia's text materials in your own books/articles/web sites or other publications, you can generally do so, but you must comply with one of the licenses that Wikipedia's text is licensed under. Many of the media files on Wikipedia are also reusable. Each media file has its own licensing statement which must be verified, and reuse of any media file must comply with its licensing.
Neither the Wikimedia Foundation nor the authors of material on Wikimedia sites provide legal advice. Wikipedia is primarily subject to U.S. law; re-users outside the U.S. should be aware that...