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.

How it works

While all articles in Wikipedia are derivative works based on the first contribution made to the article, each article must be licensed under the GFDL. 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 GFDL.

Example: David and Diana are dual-licensors under the GFDL and an incompatible License A. Gustav only licenses under the GFDL. Both the GFDL 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.

For instance,

1. David creates an article
2. Diana makes a change.
3. David makes a change.
4. Gustav makes a change.
5. Diana makes a change.

Under this scenario, versions 1 through 3 are available under the GFDL and incompatible License A, but version 4 is only available under the GFDL. 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.

Controversy

The case for multiple licenses

• To be friendly and able to use the material with other open projects which use an incompatible license other than the GFDL.
• To make licensing of material less restrictive:
  • The CC-by-sa license does not require 2 to 3 pages of legal text with each document.
  • Public domain allows totally unrestricted usage for any purpose.
• If enough people use a different compatible license, large numbers of articles can be dual licensed.
• To satisfy a copyright holder's ideological or philosophical opinions, such as a belief that information should be absolutely unrestricted (released into the public domain).
• It is not a policy but instead totally optional.

The case against multiple licenses

• A third-party can take the material and modify it under the terms of License A and not release it under the GFDL. This may create an incompatible fork which prevents those modifications from being able to be used by Wikipedia under the GFDL. Using the GFDL alone prevents this and ensures that any derived works can always be used on Wikipedia without modification. Note that under the official Wikipedia interpretation of what constitutes an aggregate work (see Wikipedia:Verbatim copying), it is already possible to add paragraphs or images which are not GFDLed and thus create an incompatible fork.
• For heavily edited articles, the process of manually sifting through the rat's nest of edits to determine whether an article, or a part of an article, is available outside the GFDL becomes more error-prone as the number of edits to the article increases. This makes it more likely that an article only available under the GFDL will be erroneously labeled otherwise, and subsequently used in violation of the license.
• One could hypothesize that some ideological fanatics might systematically revert, or eliminate, changes made only under the GFDL to their favorite articles, so that they remain available under an incompatible license.

Why it might not matter

• Figuring out who has licensed their contributions under a conceivably large number of different licenses can be cumbersome at best. It may be possible, but extremely difficult, to figure out what modifications can be used under a particular license.
• Even if those who dual-license their contributions can be identified, the dual-licensed content may not be useful. For example, only the first, third and fifth words of a given sentence may be dual licensed, while the rest are GFDL-only. Obviously, the dual-licensed content would be of very little use.
• Future amendments to the GFDL reducing the burden on the reproducer may make dual-licensing with a Creative Commons license unnecessary.

Using multiple licenses

In general, users make their multi-licensing desires known on their user page by way of a banner or some description of their wishes (See User:Jamesday for a complicated example). This is often simply accomplished by adding a pre-made template (such as {{DualLicenseWithCC-BySA}}). See the full selection of licensing templates available.

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. In addition, a user may consider releasing all minor changes into the public domain in order to avoid the problems that trivial changes may have in trying to release an article in a specific license. At the same time, meaningful non-minor changes can be released under a more restrictive license. In the case of the GNU licenses, one can specify certain restrictions, such as specifying a particular version of the license instead of any.

Using the GFDL only

Unless you specifically say otherwise, all contributions to Wikipedia are licensed under the GFDL; therefore, if you elect not to adopt additional licenses, no action is necessary. Even if you use the GFDL exclusively, you may wish to communicate your preference on your User page, such as by using {{NoMultiLicense}}.

List of terms for use

• Creative Commons License
  • Version 1.0
    • Creative Commons Attribution-ShareAlike Draft (CC-by-sa) {{DualLicenseWithCC-BySA}}
    • Creative Commons ShareAlike (CC-sa)
    • Creative Commons NonCommercial-ShareAlike (CC-nc-sa)
    • Creative Commons NoDerivs (CC-nd)
    • Creative Commons NonCommercial-NoDerivs (CC-nc-nd)
    • Creative Commons NonCommercial (CC-nc)
  • Version 2.0
    • Creative Commons Attribution-ShareAlike (CC-by-sa) {{MultiLicenseWithCC-BySA-Any}}
      • This license is very similar to the GFDL used by Wikipedia and is thus very popular.
    • Creative Commons Attribution-NonCommercial-ShareAlike (CC-by-nc-sa)
    • Creative Commons Attribution (CC-by)
    • Creative Commons Attribution-NoDerivs (CC-by-nd)
    • Creative Commons Attribution-NonCommercial-NoDerivs (CC-by-nc-nd)
    • Creative Commons Attribution-NonCommercial (CC-by-nc)
• Public domain
  • Many users do not wish their contributions to be restricted in any way.
• GNU Licenses
  • GNU General Public License (GPL)
  • GNU Lesser General Public License (LGPL)
  • GNU Free Documentation License (GFDL)
• FreeBSD Documentation License
• BSD Documentation License
• BSD license

Related pages

• w:en:Wikipedia:Userboxes/Large/Licencing
• Wikivoyage:Dual licensing
• The full selection of Creative Commons Licenses
• Unofficial Multi-Licensing FAQ

References

• This guide was partially based on the content of Guide to the Creative Commons dual-license.