The Open Source Initiative (OSI) is considered the arbiter of
open-source licenses.
The four freedoms include: running the software for any purpose,
studying and changing the source code, and distributing copies of the
original or modified source.
A permissive license allows derivative works to be licensed
differently than the original; a copyleft license requires that the
derivative use the same license as the original.
Creative Commons is a licensing scheme for non-software works that
is similar to the open-source spectrum for software.
Philosophical reasons to choose open-source licenses include
consistency with the scientific method and openness of publicly funded
research results. Another reason is that it facilitates building a
community around your software.
Most software-related business models work as well for open-source
software as for proprietary.
Open-source doesn’t guarantee that outsiders will engage with your
software. You’ll need to work to build a community of contributors and
users.
There are many OSI-approved licenses already available covering most
needs. Some publications or other venues require OSI-approved
licenses.
The variants of the GNU GPL license are among the most popular
copyleft licenses, while Apache, BSD, and MIT are among the most popular
permissive licenses.
ChooseALicense.com has
analyses of more than 40 open-source licenses along 13 different
characteristics.
Collaborators may be resctricted in their ability to contribute to
open source projects (e.g. industrial partners) or unable to copyright
their work (government employees).
You can include a Contributor License Agreement (CLA) to ensure
collaborators agree to license terms prior to committing code.
Stackoverflow content is licensed as CC BY-SA, which is incompatible
with permissive or proprietary licenses.
License and copyright around LLM-generated content is actively being
litigated.
