From Wikipedia:

[American legal scholar] Pamela Samuelson has identified eight “values” that can arise from information and works in the public domain

Possible values include:

1. Building blocks for the creation of new knowledge, examples include data, facts, ideas, theories, and scientific principle.
2. Access to cultural heritage through information resources such as ancient Greek texts and Mozart’s symphonies.
3. Promoting education, through the spread of information, ideas, and scientific principles.
4. Enabling follow-on innovation, through for example expired patents and copyright.
5. Enabling low cost access to information without the need to locate the owner or negotiate rights clearance and pay royalties, through for example expired copyrighted works or patents, and non-original data compilation.
6. Promoting public health and safety, through information and scientific principles.
7. Promoting the democratic process and values, through news, laws, regulation, and judicial opinion.
8. Enabling competitive imitation, through for example expired patents and copyright, or publicly disclosed technologies that do not qualify for patent protection.