Paraslash is licensed under the GNU General Public License, Version 2, which is generally just abbreviated as the GPL license, or just the GPL.

Check out the GPL License Quiz or take a look at the Frequently Asked Questions about the GNU GPL.

As of this writing (June 2007) the author does not see any benefits in switching to the new version 3 of the GPL just released. However, this may change once version 3 becomes widely used.