Creative Commons (CC) is a non-profit organization devoted to expanding the range of creative works available for others to build upon legally and to share. The organization has released several copyright licenses known as Creative Commons licenses. These licenses allow creators to communicate which rights they reserve, and which rights they waive for the benefit of other creators.

The original set of licenses all grant the "baseline rights". The details of each of these licenses depends on the version, and comprises a selection of four conditions:

• Attribution (by): Licensees may copy, distribute, display and perform the work and make derivative works based on it only if they give the author or licensor the credits in the manner specified by these.

• Noncommercial or NonCommercial (nc): Licensees may copy, distribute, display, and perform the work and make derivative works based on it only for noncommercial purposes.

• No Derivative Works or NoDerivs (nd): Licensees may copy, distribute, display and perform only verbatim copies of the work, not derivative works based on it.

• ShareAlike (sa): Licensees may distribute derivative works only under a license identical to the license that governs the original work. (See also copyleft.)

Mixing and matching these conditions produces sixteen possible combinations, of which eleven are valid Creative Commons licenses. Of the five invalid combinations, four include both the "nd" and "sa" clauses, which are mutually exclusive; and one includes none of the clauses. The five of the eleven valid licenses that lack the Attribution element have been phased out because 98% of licensors requested Attribution, but are still available for viewing on the website. There are thus six regularly used licenses:

1. Attribution alone (by)
2. Attribution + Noncommercial (by-nc)
3. Attribution + NoDerivs (by-nd)
4. Attribution + ShareAlike (by-sa)
5. Attribution + Noncommercial + NoDerivs (by-nc-nd)
6. Attribution + Noncommercial + ShareAlike (by-nc-sa)