Creative Commons license

# Overview
A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted "work".
A CC license is used when an author wants to give other people the right to share, use, and build upon a work that they (the author) have created. CC provides an author flexibility (for example, they might choose to allow only non-commercial uses of a given work) and protects the people who use or redistribute an author's work from concerns of copyright infringement as long as they abide by the conditions that are specified in the license by which the author distributes the work.
There are several types of Creative Commons 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. There have also been five versions of the suite of licenses, numbered 1.0 through 4.0. Released in November 2013, the 4.0 license suite is the most current.
In October 2014, the Open Knowledge Foundation approved the Creative Commons CC BY, CC BY-SA and CC0 licenses as conformant with the "Open Definition" for content and data.

# 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.
While Software is also governed by copyright law and CC licenses are applicable, the Creative Commons recommends Free and open-source software software licenses instead of Creative Commons licenses. Outside the FOSS licensing use case for software there are several usage examples to utilize CC licenses to specify a "Freeware" license model; examples are The White Chamber, Mari0 or Assault Cube. Also the Free Software Foundation recommends the CC0 as the preferred method of releasing software into the public domain.
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 Commons licenses, the user may choose either.

## Preconditions
The author, or the licenser in case the author did a contractual transfer of rights, need to have the exclusive rights on the work. If the work has already been published under a public license, it can be uploaded by any third party, once more on another platform, by using a compatible license, and making reference and attribution to the original license (e.g. by referring the URL of the original license).

## Consequences
The license is non-exclusive and royalty-free, unrestricted in terms of territory and duration, so is irrevocable, unless a new license is granted by the author after the work has been significantly modified. Any use of the work that is not covered by other copyright rules triggers the public license. Upon activation of the license, the licensee must adhere to all conditions of the license, otherwise the license agreement is illegitimate, and the licensee would commit a copyright infringement. The author, or the licenser as a proxy, has the legal rights to act upon any copyright infringement. The licensee has a limited period to correct any non-compliance.

# Types of licenses

## Attribution (CC BY)
This license lets others distribute, remix, adapt, and build upon your work, even commercially, as long as they credit you for the original creation. This is the most accommodating of licenses offered. Recommended for maximum dissemination and use of licensed materials.

## Attribution-ShareAlike (CC BY-SA)
This license lets others remix, adapt, and build upon your work even for commercial purposes, as long as they credit you and license their new creations under the identical terms. This license is often compared to copyleft free and open source software licenses. All new works based on yours will carry the same license, so any derivatives will also allow commercial use. This is the license used by Wikipedia, and is recommended for materials that would benefit from incorporating content from Wikipedia and similarly licensed projects.

## Attribution-NoDerivs (CC BY-ND)
This license lets others reuse the work for any purpose, including commercially; however, it cannot be shared with others in adapted form, and credit must be provided to you.

## Attribution-NonCommercial (CC BY-NC)
This license lets others remix, adapt, and build upon your work non-commercially, and although their new works must also acknowledge you and be non-commercial, they dont have to license their derivative works on the same terms.

## Attribution-NonCommercial-ShareAlike (CC BY-NC-SA)
This license lets others remix, adapt, and build upon your work non-commercially, as long as they credit you and license their new creations under the identical terms.

## Attribution-NonCommercial-NoDerivs (CC BY-NC-ND)
This license is the most restrictive of our six main licenses, only allowing others to download your works and share them with others as long as they credit you, but they cant change them in any way or use them commercially.