The October Open Game License (OOGL) was a copyleft license published by the RPG Library for game documents, especially those found in role-playing games. It is a modified version of the GNU Free Documentation License.
The OOGL was published in order to rectify perceived problems with the Open Gaming License so that it would be more free and open. The Open Gaming Foundation considered the OOGL to be compatible with the OGL, but the reverse might not necessarily be true.
Despite the fact that the Free Software Foundation (FSF) make their copyrighted licenses freely available, they do prohibit unauthorized modified versions from being published. The RPG Library mistakenly believed that the same copyleft freedom that applied to FSF works also applied to their licenses. When the OOGL was modified by publishers with additional clauses protecting trademarks, on May 5, 2002, Richard Stallman requested that the RPG Library cease publication. The RPG Library refused, but eventually stopped supporting the OOGL through lack of interest. It has since been officially deprecated in favor of the Creative Commons Attribution-ShareAlike License.
