[citation][nom]thr3ddy[/nom]Open Source does NOT mean that nobody owns the source code, you're confusing open source with the public domain. In fact, PSGroove comes licensed under the GPL license, which is pretty restrictive to developers who wish to reuse the source code.[/citation]
The GPL does not restrict your use, study, modification, sharing, re-engineer, etc of the source code. Only when you distribute work that integrates GPL'd source code are you restricted to distribute it covered by the GPL.
While I'd agree that there are even more liberal licenses, "pretty restrictive" seems exaggerated.