3. The third one is the Joint-Copyright PlaneShift License. This license is applied to contributors and allows the author to maintain his copyright while giving to PS the right to use his material. We give more details on that option below in this document
The above text from Planeshift\'s license notes seems to express something superfluous. The GPL - to widespread understanding - does not take away copyright from the author but only grants non-exclusive rights of usage. Hence this point 3 is already included in GPL.
As you further detail this point and forbid the contributor to use his makings in other MMORPG environments, this actually cuts down GPL. Don\'t know if you intended that.
- Randolf