GPL places no restrictions on how you USE the software.
You can use it for any purpose. You can modify it, adding or deleting code in any way you want.
If you don't redistribute the software, it ends there.
The GPL only comes into play if you redistribute the software. You then have the responsibility to pass on the source code with any modifications you've made so that subsequent users have the same rights you do.
Other licenses like BSD and MIT do not have these restrictions. You could fork and close the software, distributing binaries that do things the users might not agree with but would not be able to discern and counteract.
In the last little while I have been wondering if the negative side effects of forcing others to be open outweigh the benefits.
I don't really have a point. I just think its interesting.
MIT & friends are licenses that benefit developers. GPL family focuses on benefits to end users.
The license restricts people in what they can do with _their_ modification of that code. E.g. whether they can package _their_ modifications of it as closed.
Sounds like a restriction to me.
Sounds like freedom to me.
My freedom to shoot you is limited by your freedom to not be harmed. My freedoms have been limited but this is very fair.