Wikipedia:Multi-licensing

All text changes to Wikipedia fall under the GNU Free Documentation License (GFDL) with the copyright being kept by the original author. This is a guide for using multiple licensing of one's contributions made to Wikipedia so that they are in the public domain or licensed under alternative licenses in addition to the GFDL. A number of users have chosen to release their contributions under the Creative Commons Attribution Share-Alike license (known as "CC-by-sa"), or some other license, or even to release their contributions into the public domain. Dual- or multi-licensing is not required or suggested by Wikipedia, but some users—for a variety of ideological or other reasons—prefer to release their contributions under a wider range of terms.