Creative Commons license
A Creative Commons license is one of several public copyright licenses that allow the distribution of copyrighted works. A Creative Commons license is used when an author wants to give people the right to share, use, and even build upon a work that they have created. CC provides an author flexibility (for example, they might choose to allow only non-commercial uses of their own work) and protects the people who use or redistribute an author's work, so they don’t have to worry about copyright infringement, as long as they abide by the conditions the author has specified.
There are several types of CC licenses. The licenses differ by several combinations that condition the terms of distribution. They were initially released on December 16, 2002 by Creative Commons, a U.S. non-profit corporation founded in 2001.
Original licenses 
As of July 2011, Creative Commons licenses have been "ported" to over 50 different jurisdictions worldwide. No new ports are being started as preparations for version 4.0 of the license suite begin.
The original set of licenses all grant the "baseline rights", such as the right to distribute the copyrighted work worldwide, without changes, at no charge. The details of each of these licenses depends on the version, and comprises a selection of four conditions:
|Attribution (by)||Licensees may copy, distribute, display and perform the work and make derivative works based on it only if they give the author or licensor the credits in the manner specified by these.|
|Share-alike (sa)||Licensees may distribute derivative works only under a license identical to the license that governs the original work. (See also copyleft.)|
|The following two clauses are not free software licenses, according to either DFSG or the Free Software Foundation, and cannot be used in contexts that require these freedoms, such as Wikipedia.|
|Noncommercial (nc)||Licensees may copy, distribute, display, and perform the work and make derivative works based on it only for noncommercial purposes.|
|No Derivative Works (nd)||Licensees may copy, distribute, display and perform only verbatim copies of the work, not derivative works based on it.|
Mixing and matching these conditions produces sixteen possible combinations, of which eleven are valid Creative Commons licenses and five are not. Of the five invalid combinations, four include both the "nd" and "sa" clauses, which are mutually exclusive; and one includes none of the clauses. Of the eleven valid combinations, the five that lack the "by" clause have been retired because 98% of licensors requested attribution, though they do remain available for reference on the website. This leaves six regularly used licenses:
- Attribution alone (by) –
- Attribution + NoDerivatives (by-nd) –
- Attribution + ShareAlike (by-sa) –
- Attribution + Noncommercial (by-nc) –
- Attribution + Noncommercial + NoDerivatives (by-nc-nd) –
- Attribution + Noncommercial + ShareAlike (by-nc-sa) –
For example, the Creative Commons Attribution (BY) license allows one to share and remix (create derivative works), even for commercial use, so long as attribution is given.
Since 2004, all current licenses require attribution of the original author. The attribution must be given to "the best of [one's] ability using the information available". Generally this implies the following:
- Include any copyright notices (if applicable). If the work itself contains any copyright notices placed there by the copyright holder, those notices must be left intact, or reproduced in a way that is reasonable to the medium in which the work is being re-published.
- Cite the author's name, screen name, or user ID, etc. If the work is being published on the Internet, it is nice to link that name to the person's profile page, if such a page exists.
- Cite the work's title or name (if applicable), if such a thing exists. If the work is being published on the Internet, it is nice to link the name or title directly to the original work.
- Cite the specific CC license the work is under. If the work is being published on the Internet, it is nice if the license citation links to the license on the CC website.
- Mention if the work is a derivative work or adaptation, in addition to the above, one needs to identify that their work is a derivative work i.e., “This is a Finnish translation of [original work] by [author].” or “Screenplay based on [original work] by [author].”
Non-commercial licenses 
The "non-commercial" option included in some Creative Commons licenses is controversial in definition, as it's sometimes unclear what can be considered a noncommercial setting, and application, since its restrictions differ from the principles of open content promoted by other permissive licenses.
Applicable works 
Work licensed under a Creative Commons License is governed by applicable copyright law. This allows Creative Commons licenses to be applied to all work falling under copyright, including: books, plays, movies, music, articles, photographs, blogs, and websites. Creative Commons does not recommend the use of Creative Commons licenses for software.
However, application of a Creative Commons license may not modify the rights allowed by fair use or fair dealing or exert restrictions which violate copyright exceptions. Furthermore, Creative Commons Licenses are non-exclusive and non-revocable. Any work or copies of the work obtained under a Creative Commons license may continue to be used under that license.
In the case of works protected by multiple Creative Common Licenses, the user may choose either.
Retired licenses 
Due to either disuse or criticism, a number of previously offered Creative Commons licenses have since been retired, and are no longer recommended for new works. The retired licenses include all licenses lacking the Attribution element other than CC0, as well as the following four licenses:
- Developing Nations License: a Developing Nations license, which only applies to countries deemed by the World Bank as a "non-high-income economy". Full copyright restrictions apply to people in other countries.
- Sampling: parts of the work can be used for any purpose other than advertising, but the whole work cannot be copied or modified
- Sampling Plus: parts of the work can be copied and modified for any purpose other than advertising, and the entire work can be copied for noncommercial purposes
- NonCommercial Sampling Plus: the whole work or parts of the work can be copied and modified for noncommercial purposes
Public domain 
Besides licenses, Creative Commons also offers a way to release material into the public domain through CC0, a legal tool for waiving as many rights as legally possible, worldwide. Development of CC0 began in 2007 and the tool was released in 2009.
In 2010, Creative Commons announced its Public Domain Mark, a tool for labeling works already in the public domain. Together, CC0 and the Public Domain Mark replace the Public Domain Dedication and Certification,  which took a U.S.-centric approach and co-mingled distinct operations.
Partial list of projects that release contents under Creative Commons licenses 
- Internet Archive (Various)
- Anatomography (CC BY-SA)
- Association for Progressive Communications (CC BY-SA)
- ccMixter (mostly CC BY-NC)
- Citizendium (CC BY-SA)
- Copernicus Publications (CC BY)
- European Geosciences Union (CC BY)
- The Freesound Project (CC0, CC BY, CC BY-NC and Sampling Plus)
- Free Music Archive (Various)
- Identi.ca (CC BY)
- Jamendo (Various)
- Khan Academy (CC BY-NC-SA)
- knol (mostly, CC BY-SA or CC BY-NC-SA)
- Mushroom Observer (CC BY-SA or CC BY-NC-SA)
- Open Courseware (CC BY-NC-SA)
- Open Game Art (CC BY and -SA 3.0 without NC, CC0)
- PLOS One (CC BY)
- The Saylor Foundation (CC BY)
- Stack Overflow (CC BY-SA)
- Wikia (CC BY-SA, since June 2009)
- WikiEducator (default CC BY-SA, also CC-BY and CC0)
- Wikinews (CC BY)
- Wikipedia (CC BY-SA, since June 2009)
- Wikitravel (CC BY-SA)
- Wikivoyage (CC BY-SA)
- xkcd (CC BY-NC)
See also 
- Creative Commons jurisdiction ports
- Free culture
- Free music
- Free software
- Non-commercial educational
- "CC Affiliate Network". Creative Commons. Retrieved July 8, 2011.
- "Baseline Rights". Creative Commons. June 12, 2008. Retrieved February 22, 2010.
- "Retired Legal Tools". Creative Commons. Retrieved May 31, 2012.
- Announcing (and explaining) our new 2.0 licenses
- "Creative Commons Licenses". Creative Commons. Retrieved February 22, 2010.
- "Creative Commons — Attribution 3.0 United States". Creative Commons. November 16, 2009. Retrieved February 22, 2010.
- "Frequently Frequently Asked Questions". Creative Commons. February 2, 2010. Retrieved February 22, 2010.
- Defining Noncommercial report published"
- The Case for Free Use: Reasons Not to Use a Creative Commons -NC License
- "Creative Commons Legal Code". Creative Commons. January 9, 2008. Retrieved February 22, 2010.
- Creative Commons FAQ: Can I use a Creative Commons license for software?
- Lessig, Lawrence (June 4, 2007). "Retiring standalone DevNations and one Sampling license". Creative Commons. Retrieved July 5, 2007.
- "Developing Nations License". Creative Commons. Retrieved 9 April 2012.
- "Sampling 1.0". Creative Commons. Retrieved 9 April 2012.
- "Sampling Plus 1.0". Creative Commons. November 13, 2009. Retrieved 9 April 2012.
- "NonCommercial Sampling Plus 1.0". Creative Commons. November 13, 2009. Retrieved 9 April 2012.
- "CC0". Creative Commons. Retrieved February 22, 2010.
- "Creative Commons Launches CC0 and CC+ Programs" (Press release). Creative Commons. December 17, 2007. Retrieved February 22, 2010.
- Baker, Gavin (January 16, 2009). "Report from CC board meeting". Open Access News. Retrieved February 22, 2010.
- Expanding the Public Domain: Part Zero
- Marking and Tagging the Public Domain: An Invitation to Comment
- "Copyright-Only Dedication (based on United States law) or Public Domain Certification". Creative Commons. August 20. 2009. Retrieved February 22, 2010.
- "Using CC0 for public domain software". Creative Commons. April 15. 2011. Retrieved May 10, 2011.
|Find more about Creative Commons license at Wikipedia's sister projects|
|Definitions and translations from Wiktionary|
|Media from Commons|
|Learning resources from Wikiversity|
|Quotations from Wikiquote|
|Source texts from Wikisource|
|Database entry #Q43449 on Wikidata|
- Official site
- Full selection of licenses
- Creative Commons Licenses Compatibility Wizard
- Citizen's guide to using Creative Commons licenses
- A human readable summary of version 2.5 of the Creative Commons CC-BY-SA license. (Retrieved 2010-04-10).
- Legal code of the CC-BY-SA 3.0 License.