Creative Commons
Creative Commons (CC) is a nonprofit organization. CC has developed a series of licenses that provide opportunities for creators and owners of copyrighted works to more easily share their creative works under a licensing framework, thus substantially avoiding copyright questions in many circumstances.
The various CC licenses in essence functionally "pre-define" how a user of the work can make copies, distribute, perform and make other uses without analyzing the copyright implications of those uses. The CC license come in many flavors and address legal, technological, and lay perspectives in their language and structure.
Educators and others are increasingly attaching CC licenses to certain works requiring only that the user provide attribution in using the work. Thus, the user may use the work in many important and diverse ways by simply providing information about the creator of the work.
Using and sharing CC licensed works requires careful investigation of the "terms of use" defined in the associated CC license. Using CC works can provide important opportunities to define the use of creative works but like all licenses require an understanding of that licensing relationship. The CC license language is sometimes more straightforward than copyright law. However, reading it closely is still necessary and important in order to understand the rights of use or how your work would be available under a CC license.