# Copyright Law

Protects expression, not ideas.

- Relatively long duration.  Life of the author plus 70 years in the U.S.
- Software is considered a literary work.
- [[Fair use]] is not considered infringement.
- Registration is not required.  Ownership immediately vests in the author.  But in the U.S., registration is a prerequisite for filing a legal claim of infringement.
- [[Joint authorship]] is an interesting doctrine that tries to distinguish an author receiving assistance versus the existence of a second author with shared legal ownership.
- Transfers must be in writing, but licenses may be oral, or even just implied.
- [[notice-and-takedown]] strikes an interesting balance and has stood the test of time in the U.S., having existed more or less unchanged since 1998.

[//begin]: # "Autogenerated link references for markdown compatibility"
[Fair use]: fair-use.md "Fair Use"
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