Context:
Permissive licenses (commonly referred to as “cuck licenses”) like the MIT license allow others to modify your software and release it under an unfree license. Copyleft licenses (like the Gnu General Public License) mandate that all derivative works remain free.
Andrew Tanenbaum developed MINIX, a modular operating system kernel. Intel went ahead and used it to build Management Engine, arguably one of the most widespread and invasive pieces of malware in the world, without even as much as telling him. There’s nothing Tanenbaum could do, since the MIT license allows this.
Erik Andersen is one of the developers of Busybox, a minimal implementation of that’s suited for embedded systems. Many companies tried to steal his code and distribute it with their unfree products, but since it’s protected under the GPL, Busybox developers were able to sue them and gain some money in the process.
Interestingly enough, Tanenbaum doesn’t seem to mind what intel did. But there are some examples out there of people regretting releasing their work under a permissive license.
I published some packages under MIT a couple of years ago. It is difficult to understand at first, I was happy with the license because anyone could use it like they want.
Today, I understand that I want to use GPL. With GPL everyone can use the code like they want and I can use their code like I want.
For writing an application GPL is fine if you don’t want anyone to profit from your work and if they make changes, contribute back.
Things are a little bit more complex if you are writing a library or code that is meant to be included in another application.
If you use GPL you might get rejected even by other open source applications, as GPL might be understandable as it will change license off the application or be outright incompatible.
This was the case with cursor library after author changed license everyone stopped using it: https://github.com/GijsTimmers/cursor/commit/885156333ac9ca335a587b1dd08964074313f026
The most ironic thing is that he created package from stack overflow answer:
https://github.com/GijsTimmers/cursor/blob/master/cursor/cursor.py
The original author never said they are releasing copyright or are making it public domain.
Isn’t this why LGPL exists?
It is
Technically you can. There are two popular models: Lua model and RedHat model. In first you are paid to develop requeated features, in second for support.