Much content on Wikipedia and other Wikimedia projects is released under the GNU Free Documentation License, or GFDL (alongside Creative Commons Attribution/Share-Alike License). What this means is sometimes misconstrued by users and readers.
What the GFDL is not
- The GFDL is not public domain. All contributions are copyrighted by their individual authors, unless they choose to release them into the public domain. Material licensed under the GFDL is not free in the way that public domain material is free. Derivative works must be licensed under the GFDL, and credit to the original authors (copyright owners) must be maintained.
- The GFDL is not entirely compatible with other licenses such as the Berkeley Software Distribution (BSD) or Creative Commons (CC). BSD content can be added to GFDL content, but GFDL content can not be added to BSD content. Some users choose to multi-license their contributions under these alternatives in addition to the GFDL.
- The GFDL does not transmit the ownership of copyright on content. Wikipedia does not own the copyright on a user's contributions; individual users own their edits.
- The GFDL is not a way of avoiding copyright law. Copyrighted material for which an editor does not own or have permission to use should not be added to Wikipedia. Similarly, copyrighted material for which an editor does have permission to use, but not under the GFDL or other compatible licenses, should not be added to Wikipedia either. There are some exceptions, such as material which falls under the fair use provision of United States copyright law. Album covers are an example of material which is believed to be legally acceptable on Wikipedia under fair use. Wikipedia seeks to remove content which is not legally acceptable through its system of reporting possible copyright violations (see Wikipedia:Copyright problems).