Share-alike
Share-alike (🄎) is a copyright licensing term, originally used by the Creative Commons project, to describe works or licenses that require copies or adaptations of the work to be released under the same or similar license as the original.[1] Copyleft licenses are free content or free software licenses with a share-alike condition.
Two currently-supported Creative Commons licenses have the ShareAlike condition: Creative Commons Attribution-ShareAlike (a copyleft, free content license) and Creative Commons Attribution-NonCommercial-ShareAlike (a proprietary license).
The term has also been used outside copyright law to refer to a similar plan for patent licensing.[2]
Copyleft
[edit ]Copyleft or libre share-alike licenses are the largest subcategory of share-alike licenses. They include both free content licenses like Creative Commons Attribution-ShareAlike and free software licenses like the GNU General Public License. These licenses have been described pejoratively as viral licenses, because the inclusion of copyleft material in a larger work typically requires the entire work to be made copyleft. The term reciprocal license has also been used to describe copyleft, but has also been used for non-libre licenses (see, for example, the Microsoft Limited Reciprocal License).
Free content and software licenses without the share-alike requirement are described as permissive licenses.
Creative Commons
[edit ]As with all six licenses in the current Creative Commons suite, CC Attribution-ShareAlike and CC Attribution-NonCommercial-ShareAlike require attribution. According to Creative Commons, the advantage of this license is that future users are not able to add new restrictions to a derivative of your work; their derivatives must be licensed the same way.[3]
The 3.0 and 4.0 version of the ShareAlike licenses include a compatibility clause, allowing Creative Commons to declare other licenses as compatible and therefore derivatives may use these instead of the license of the original work.
Version history
[edit ]![[icon]](/index.cgi/contrast/https://en.wikipedia.org/wiki/File:Wiki_letter_w_cropped.svg){kind=link}
Over the years, Creative Commons has issued 5 versions of the BY-SA and BY-NC-SA licenses (1.0, 2.0, 2.5, 3.0 and 4.0).
- Attribution-ShareAlike Version 1.0 Generic[4] and Attribution-NonCommercial-ShareAlike Version 1.0 Generic[5] – Released December, 2002
- Attribution-ShareAlike Version 2.0 Generic[6] and Attribution-NonCommercial-ShareAlike Version 2.0 Generic[7] – Released May, 2004
- Attribution-ShareAlike Version 2.5 Generic[8] and Attribution-NonCommercial-ShareAlike Version 2.5 Generic[9] – Released June, 2005
- Attribution-ShareAlike Version 3.0 Unported[10] and Attribution-NonCommercial-ShareAlike Version 3.0 Unported[11] – Released March, 2007
- Attribution-ShareAlike Version 4.0 International[12] and Attribution-NonCommercial-ShareAlike Version 4.0 International[13] – Released November, 2013
See also
[edit ]References
[edit ]- ^ "Glossary". Archived from the original on 2012年02月22日. Retrieved 2012年03月05日.
- ^ Davis, Ian (2011年08月08日). "Share-Alike Patents". Archived from the original on 2012年04月03日. Retrieved 2012年03月05日.
- ^ "Share Alike". CC Wiki. 2011年01月24日. Archived from the original on 2017年08月13日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-ShareAlike 1.0 Generic — CC BY-SA 1.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2017年08月25日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-NonCommercial-ShareAlike 1.0 Generic — CC BY-NC-SA 1.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2017年08月25日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-ShareAlike 2.0 Generic — CC BY-SA 2.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2011年02月22日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-NonCommercial-ShareAlike 2.0 Generic — CC BY-NC-SA 2.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2017年08月13日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-ShareAlike 2.5 Generic — CC BY-SA 2.5". Creativecommons.org. 1999年02月22日. Archived from the original on 2011年02月23日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-NonCommercial-ShareAlike 2.5 Generic — CC BY-NC-SA 2.5". Creativecommons.org. 1999年02月22日. Archived from the original on 2017年08月12日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-ShareAlike 3.0 Unported — CC BY-SA 3.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2011年02月22日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-NonCommercial-ShareAlike 3.0 Unported — CC BY-NC-SA 3.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2018年02月15日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-ShareAlike 4.0 International — CC BY-SA 4.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2016年12月21日. Retrieved 2017年08月13日.
- ^ "Creative Commons — Attribution-NonCommercial-ShareAlike 4.0 International — CC BY-NC-SA 4.0". Creativecommons.org. 1999年02月22日. Archived from the original on 2017年08月13日. Retrieved 2017年08月13日.