Z:gnu-www-ja-x--b067ee-To copyleft or not to copyleft/en

To copyleft or not to copyleft? That is one of the major controversies in the free software community. The idea of copyleft is that we should fight fire with fire&mdash;that we should use copyright to make sure our code stays free. The GNU General Public License (GNU GPL) is one example of a copyleft license.