Most free software is not copyleft though, and fewer and fewer new free software projects are choosing copyleft licenses.
Ultimately copyleft is mostly a bureaucratic exercise, and it ends up stifling collaboration in all but the most hostile environments (such as the one Linux faced in its early days).
Ultimately copyleft is mostly a bureaucratic exercise, and it ends up stifling collaboration in all but the most hostile environments (such as the one Linux faced in its early days).