Creative Commons is a non-profit organization based in California, USA. They publish a variety of free licenses for software, artworks and other material subject to Copyright. Their licenses vary from being very liberal to somewhat restrictive. It is therefore wise to briefly look at what specific license a given piece of Creative Commons licensed work is actually licensed under to learn what is and is not allowed to do under a particular license.
The Attribution-ShareAlike license (CC BY-SA) allows you to do almost anything with a work licensed under it as long as you give the original author credit and license divided works under the same license.
The Creative Commons CC BY-SA page states:
"You are free to:
- Share - copy and redistribute the material in any medium or format
- Adapt - remix, transform, and build upon the material for any purpose, even commercially.
The licensor cannot revoke these freedoms as long as you follow the license terms.
Under the following terms:
- Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
- ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
- No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits."
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
This Creative Commons "license" is strictly not a license, it is a general statement granting the work in question into the public domain. Everything with a Public Domain Dedication can be used freely for any purpose. Text and images in the public domain can be modified, remixed, used and re-used. Commercial use is allowed.
"The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission."
The Creative Commons website has translations of the public domain declaration in many languages.