Unless otherwise stated, all edits to Wikia fall under a free license with the copyrights being retained by the original author. Every user has the option of multiple licensing their own copyrighted contributions made to Wikia so that the content they add can be reused under an alternative license other than the CC-BY-SA. Dual- or multi-licensing is not required, but is an option if you prefer to release your contributions under a wider range of terms.
How it works Edit
While all articles in Wikia are derivative works based on the first edit made to the article, each article must be licensed under a license such as CC-BY-SA. However, individual contributions are not by themselves derivative works because they do not contain any of the original work, as the copyright still remains with the author. It is within one's rights to license those contributions under any terms one prefers, so long as one does it in addition to also being covered under the main license of the wiki.
David and Diana are dual-licensors under the CC-BY-SA and an incompatible License A. Gustav only licenses under the CC-BY-SA. Both the CC-BY-SA and License A may be used in the following cases:
- The initial revision started by David or Diana.
- Any modifications by David or Diana up to, but not including, a modification made by Gustav.
- Possibly any changes made to the article after Gustav by David or Diana which do not include the modification made by Gustav.
- David creates an article
- Diana makes an edit.
- David makes an edit.
- Gustav makes an edit.
- Diana makes an edit.
Under this scenario, versions 1 through 3 are available under the CC-BY-SA and incompatible License A, but version 4 is only available under the CC-BY-SA. Version 4 may be fully available if Gustav's edit was a trivial one that wouldn't cause anyone to care, such as fixing a typographical error. Version 5 is probably available if it subtracts the modification made by Gustav. For instance, if Gustav adds a specific paragraph that is separate from the rest of the article, the article minus that paragraph can be used under both licenses. For all other usage, such as if Diana's modification was derived from Gustav's modification, you must convince Gustav to release his contributions under License A to use them. In the case of Version 4 and 5, one must use some common sense in order to tell what qualifies as being covered under both licenses and what does not.
How to multi-license Edit
By default edits to most Wikia wikis are released exclusively under the CC-BY-SA. If you want to multi-license, the easiest way to do this is to make your multi-licensing desires known on your user page by way of a banner or some description of their wishes. The scope of a license may vary. For instance, a user may choose to license main namespace changes in one license and talk namespace changes in another.