Free Software categories
What people call 'free' when they mean "no-fee" (depicted above with an eliptical outline) is not the same as 'Free Software', which guarantees freedom. Truly free software is copylefted software under the GPL license.
See https://www.gnu.org/philosophy/categories.html for some definitions of various kinds of software categorized by licensing.
The best license to choose to make your program free is to choose the GPLv3 or later. This license adds protections against patents and also other things that could threaten user freedom.
Choosing
If you choose free, choose the GPLv3 or later.
If you don't choose GPLv3, then choose the Apache license because at least that has a patent termination clause if someone sues you. In other words, the people like Microsoft who use the MIT license in their works have and will try to use patent law to take away the rights they've given you with the software license.
If you are copyrighting documentation, wikis, databases or free culture / artistic content such drawings, photos, music, video etc. then choose the Creative Commons license.
NOT free
All the major software companies have 'open source' software. This is because
- The Open Source model benefits them (getting development, Quality Control and distribution for free).
- It enables them to win the hearts and minds of the public/developers by portraying themselves as acting altruistically. In other words, they've co-opted the term 'free' and equate it with 'open source'. But open source does not mean Free Software. Open Source, ('proprietary-friendly') licenses like The MIT license and the Apache Software License allow a commercial interest to take 'your' code, and turn it into a proprietary version that they don't share with you. It's been done time and time again. So, if you like the idea of some company standing on your shoulders and you getting nothing in return, then choose 'open source'.
Examples
- Apple
- Swift programming language. Apache license [1]
- https://www.tensorflow.org/ TensorFlow machine learning system. Apache 2.0 license
You can see in the following exerpts taken from the project website (emphasis added) that Google is trying to benefit over competitors by using developers.
Who Can Use TensorFlow?
TensorFlow is for everyone. It's for students, researchers, hobbyists, hackers, engineers, developers, inventors and innovators and is being open sourced under the Apache 2.0 open source license.
TensorFlow is not complete; it is intended to be built upon and extended. We have made an initial release of the source code, and continue to work actively to make it better. We hope to build an active open source community that drives the future of this library, both by providing feedback and by actively contributing to the source code.
Why Did Google Open Source This?
If TensorFlow is so great, why open source it rather than keep it proprietary? The answer is simpler than you might think: We believe that machine learning is a key ingredient to the innovative products and technologies of the future. Research in this area is global and growing fast, but lacks standard tools. By sharing what we believe to be one of the best machine learning toolboxes in the world, we hope to create an open standard for exchanging research ideas and putting machine learning in products. Google engineers really do use TensorFlow in user-facing products and services, and our research group intends to share TensorFlow implementations along side many of our research publications.
- Microsoft
- .NET Core The MIT License[2] and the rest of their "foundation projects".
Comparison
wp:Comparison of free and open-source software licenses More info on various licenses and comments about them are at https://www.gnu.org/licenses/license-list.html
The Mozilla Foundation publishes some information on software patents e.g. https://www.mozilla.org/en-US/about/patents/license/ as well as software licensing e.g. https://developer.mozilla.org/en-US/Add-ons/Overlay_Extensions/Firefox_addons_developer_guide/Appendix:_What_you_should_know_about_open-source_software_licenses