Creative Commons is a nonprofit organization that offers copyright licenses for digital work.
No registration is necessary to use the Creative Commons licenses. Instead, content creators select which of the organization's six licenses best meets their goals, then tag their work so that others know under which terms and conditions the work is released. Users can search the CreativeCommons.org website for creative works such as music, videos, academic writing, code or images to use commercially or to modify, adapt or build upon.
The six categories of licenses offered are:
Attribution - lets others distribute, remix, tweak and build upon work, even commercially, as long as they credit the creator for the original work.
Attribution-NoDerivs - allows for commercial and non-commercial redistribution, as long as the work is passed along unchanged and in whole, crediting the creator.
Attribution-NonCommercial-ShareAlike - lets others remix, tweak, and build upon work for non-commercial purposes, as long as they credit the creator and license any new creations under the identical terms.
Attribution-ShareAlike - lets others remix, tweak, and build upon work for commercial and non-commercial purposes, as long as they credit the creator and license new creations under the identical terms.
Attribution-NonCommercial - lets others remix, tweak, and build upon work for non-commercial purposes, crediting the creator. Derivative works do not have to be licensed under the same terms.
Attribution-NonCommercial-NoDerivs - allows others to download work and share it as long as they credit the creator, don't change the work in any way or use it for commercial purposes.