Items in the “public domain” are not protected by intellectual property laws such as copyright, trademark, or patent laws. Anyone can use a public domain work without obtaining permission.
Creative Works are usually placed in the public domain for the following reasons:
As of January 2020, any work created prior to 1925 is considered to be in the public domain.
Creative Commons is a nonprofit that facilitates the sharing and reuse of original works.
Creators select the type of license that enables others to use their work in specified ways without fear of copyright infringement or obtaining individual permissions.
| Type of Creative Commons License | Can be distributed and requires attribution | Allows for modifications | Requires same license for derivative works | Can be used for commercial purposes |
|---|---|---|---|---|
CC BY : Attribution |
Yes  &  |
Yes | No | Yes |
| CC BY-SA : Attribution-ShareAlike  |
Yes & |
Yes | Yes  |
Yes |
| CC BY-NC : Attribution-NonCommercial  |
Yes & |
Yes | No | No  |
CC BY-NC-SA : Attribution-NonCommercial-ShareAlike |
Yes & |
Yes | Yes |
No |
| CC BY-ND : Attribution-NoDerivatives  |
Yes & |
No  |
No derivatives permitted | Yes |
| CC BY-NC-ND : Attribution-NonCommercial-NoDerivatives  |
Yes & |
No |
No derivatives permitted | No |
BY Must give credit to creator
SA Modified work must be shared under same license (ShareAlike)
NC Cannot be used for commercial purposes (NonCommercial)
ND Does not allow for derivatives or adaptations (No Derivatives)
In cases where a formal citation is unnecessary, you must still credit the creator of the work. Creative Commons recommends the use of the acronym TASL, which stands for Title, Author, Source, and License. You will also want to note any modifications made to the work.
Examples of good attributions are available on the Creative Commons Wiki.