A copyright owner may grant rights to the public to use a protected work. That grant could be a simple statement on the work explaining the allowed uses, or it may be a selection of a Creative Commons license. Similarly, the movement to make works "open access" or "open source" is a choice by the owner of rights to make works available to the public.
Creative Commons is a non-profit organization that provides free copyright licenses designed to make a simple and standardized way to give the public permission to share and use a creative work. Creative Commons licenses may be applied to any type of work, including educational resources, music, photographs, databases, government and public sector information, and many other types of material. The only categories of works for which Creative Commons does not recommend its licenses are computer software and hardware.
All Creative Commons licenses are non-exclusive: creators and owners can enter into additional, different licensing arrangements for the same material at any time. All Creative Commons licenses require that users provide attribution (BY) to the creator when the material is used and shared. Some licensors choose the BY license, which requires attribution to the creator as the only condition to reuse of the material. The other five licenses combine BY with one or more of three additional license elements: NonCommercial (NC), which prohibits commercial use of the material; NoDerivatives (ND), which prohibits the sharing of adaptations of the material; and ShareAlike (SA), which requires adaptations of the material be released under the same license.
CC0 enables scientists, educators, artists and other creators and owners of copyright- or database-protected content to waive those interests in their works and thereby place them as completely as possible in the public domain, so that others may freely build upon, enhance and reuse the works for any purposes without restriction under copyright or database law.
In contrast to CC’s licenses that allow copyright holders to choose from a range of permissions while retaining their copyright, CC0 empowers yet another choice altogether – the choice to opt out of copyright and database protection, and the exclusive rights automatically granted to creators – the “no rights reserved” alternative to our licenses.
This license lets others distribute, remix, tweak, 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.
This license lets others remix, tweak, 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.
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.
This license lets others remix, tweak, and build upon your work non-commercially, and although their new works must also acknowledge you and be non-commercial, they don’t have to license their derivative works on the same terms.
This license lets others remix, tweak, and build upon your work non-commercially, as long as they credit you and license their new creations under the identical terms.
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 can’t change them in any way or use them commercially.