First when I got into game design I did not bother that much about licenses, I thought open source is open source. Torque3D was MIT-license, which is a liberal license, so I thought, well good for me that the license is so liberal and I just kept it as it is.
Then I had GPL enthusiasts trying to compel me to change my project to GPL license, since GPL was supposedly much better and more "free", since it would ensure the project staying open source and nobody could "steal" from it without giving his changes back and it would also motivate other people from the GPL enthusiasts camp to contribute to my project.
So I began to look more deeply into the license issue and the benefits and drawbacks of the different licenses, since I don't want to act emotional wihtout doing proper research first. After some deeper investigation I not only found that the GPL-guys arguments were wrong, but that the truth was more like the exact opposite. Now let us break down the arguments for the GPL one by one:
Argument 1: GPL is supposedly more free, since it is copyleft license, which forces through a license agreement which is the GPL itself everyone to keep the project free and give away all their contributions to the program also for free.
Counter argument: This in itself is already a pretty big contradiction, since freedom is absence of force, but the GPL tries to force people to be more free, which is illogical and impossible. Freedom can only happen voluntarily, which requires a choice, which does not exist in the copyleft case and also does not exist in the copyright case, it is like two sides of the same coin. Copyright only allows people with the copyright to use the software and copyleft only allows people who agree with the copyleft to use the software.
Argument 2: GPL ensures the software to stay open source and ensures that everyone who uses it will contribute the changes back under the GPL, which results in a viral grownth of the software as well as users and contributors.
Counter argument: Yes GPL may ensure the software to stay open source through its very strict license terms regarding that, at least in theory, in practice it requires lots of legal battles and it is yet to be proven how good these license terms hold up in court. Regarding ensuring the grownth of the projects by forcing contributions back into the project under the same license, it has pretty much the exact opposite effect, since the big majority of potential contributors do not agree with the GPL and therefore will not contribute anything. Those people not agreeing to the license terms will either:
a) Not use the software at all and probably use a competitors product
b) Steal it, ignore the license terms and hope nobody finds out
c) Write their own code from scratch
All those options are pretty counterproductive, the GPL says you either have to agree 100% with it and stick to it forever or chose one of those very stupid solutions listed above, there is no middle ground.
Argument 3: You can still make money with GPL software.
Counter argument: Yes theoretically you can charge money for GPL software, but practically this is almost impossible as there is no mechanism that obligates users to pay anything and there never can be as defined by the license terms. So for money making with the GPL you are left with hoping that someone voluntarily subsidizes you or just begging for money, but begging for money works for everyone and does not require do be productive at all, so you would probably just be better off with spending your time begging and not wasting time with being productive.
So to sum it up what will happen, if you put your project under the GPL license is:
1. Your program will be less free
2. Your project will most likely die
3. You will most likely ruin yourself financially
4. As a bonus you will likely attract lots of incompetent weirdos into your project from that certain community and at the same time chase away skilled contributors.
5. You most likely cannot revert that downfall, since once GPL always GPL, yes you can change the license of your own work, but as soon as your project is infected with other peoples GPL code, it becomes close to impossible to convince the GPL fanatics to change their code license as well.
Yes there may be a few exceptions where the GPL model works, since for the end user it is quite beneficial to have a free product, but the developers have to be fully subsidized by some large companies or the goverment or be stupid enough to work for free (like me), but for developers the GPL is probably one of the most effective methods ever invented to send your project into the eternal development hell, but at least you will have good company, as the development hell is already full of many dead nonexistant open source projects, with many nonexistant open source developers.