Creative Commons Licenses are a type of open licenses that you can apply to your work to indicate you are happy to share the work under certain conditions.
They are sometimes described as an alternative to copyright, however Creative Commons does not mean you give up the copyright in your work, or your right to be acknowledged as the creator of a work.
Typically Creative Commons licenses are added to online content, and search engines are increasingly able to identify content that has been shared under these licenses because in addition to the legal document, there is a machine readable license.
There are six different license types, with the most permissive being the CC-BY (Creative Commons Attribution) License and most restrictive being the CC-BY-NC-ND (Creative Commons Attribution Non-commercial No Derivatives) license. The licenses allow you to specify if you wish your work to be used for commercial purposes and if you require the person re-using your work to share it under the same license, or if you are happy with derivative works being created from your work.