The public domain contains works that have no copyright on them, either because the author dedicated it to the public domain or because copyright has expired.
The public domain is the place for all works which are free to the public. They do not normally restrict use. They may have been brought to the public domain through multiple ways, including but not limited to:
- Expiry of intellectual property
- Forfeited rights
- Inapplicable rights
- Placed in public domain by law, such as the work of a US Government employee
Furthermore, depending by countries, works automatically fall into the public domain after a certain period of time. However, it is important to note that not all legal jurisdictions have the concept of a public domain.
The Creative Commons cc0 license attempts to solve this problem.