Commercial exploitation of Freedoom: an FAQ

Since Freedoom's inception, several people have made attempts to commercially exploit it. For the most part, doing this is perfectly legal, but every now and then this subject comes up and I think it's worth writing an FAQ about it. Hopefully this thread can be linked to in future whenever this subject comes up.

Is it legal to sell Freedoom or modified versions of Freedoom?

Yes. Freedoom is licensed as Free software, and the ability to sell it and distribute modified versions is a requirement for it to be considered free.

There is a single restriction: the Freedoom license (the modified BSD license) requires that a copy of the license be distributed with all copies. This guarantees attribution to the Freedoom team.

I found a rebranded version of Freedoom on the app store for my favorite mobile phone. Isn't this bad?

In a way it's actually good, as it's making Freedoom available to more people. However, some people are understandably uncomfortable when the uploader is charging a fee, especially if they haven't done much work to provide the port.

If you really dislike this, the best thing to do is to compete: make your own Freedoom package and make it available for free. This makes Freedoom available to even more people. Alternatively you could charge a small fee as well and donate to the money you make to charity (like the Free Software Foundation, which hosts Freedoom's website).

The person selling Freedoom hasn't included any credit to the project. What should we do?

Technically if they don't include a copy of the Freedoom license then they're in violation of it. Sometimes people don't realise they have to do this, so the best thing to do is send a politely-worded email to them.

Couldn't we change the license to stop this?

The Freedoom project was started to create an IWAD file that is free software. If commercial use was prohibited, it would no longer meet the definitions of free software or open source. This would be a worse situation, because Freedoom would then be removed from distributions of various free operating systems - Debian and Ubuntu are examples.

Charging a fee for copies of Freedoom isn't really within the spirit of the project, but apart from potentially bruising some egos it doesn't cause any real harm, and the alternative is worse. It's better to stick with a free license because it better fits into the larger ecosystem of Free Software in which Freedoom exists. The Doom source code itself, for example, is released under the GNU GPL, which allows the same thing.