Shared works - whether copyright free or made available under a free license - allow creators and users to share their knowledge and creativity with the world, in the classroom and beyond.
![Creative commons license spectrum between public domain (top) and all rights reserved (bottom). Left side indicates the use-cases allowed, right side the license components. The dark green area indicates Free Cultural Works compatible licenses, the two green areas compatibility with the Remix culture. The bright green area alone can be seen as similar to the "fair use" concept, and the yellow area to the "freeware" concept.](//libapps.s3.amazonaws.com/accounts/84543/images/Creative_commons_license_spectrum.svg.png)
No Rights Reserved - Public domain
When a work is not protected by copyright (either by design or the expiration of a copyright term) it enters the public domain, a realm where no rights are reserved.
Some Rights Reserved - Creative Common licenses
Open licenses, such as those provided by Creative Commons, allow copyright holders to grant permissions to users in a simple, straightforward manner, while still retaining specified rights - some rights reserved.
All Rights Reserved - Copyright by default
In copyright law, by default, all rights are reserved, or held, for the copyright holder.