The Open Game License is a public copyright licence created by Wizards of the Coast to licence parts of their tabletop game Dungeons & Dragons 3rd edition (at the time, the world's most popular roleplaying game).
Chris Sakkas tried to start a discussion about whether the OGL should be accepted under the Open Definition on the Open Definition mailing list, but it was met with no response. His thoughts are posted here for future reference:
In 2000 the world's most popular tabletop roleplaying game, Dungeons & Dragons, had its third edition released. A large chunk of the game—most of its rules and some descriptive text—was released under the Open Game License (OGL), a share-alike public copyright licence.
To my knowledge, that was the first time that a market leader adopted a public copyright licence. The OGL was hugely influential within the tabletop roleplaying game industry: many products continue to be released under the OGL, there are databases of OGL content, and D&D's main competitor—Pathfinder—is also under the OGL.
The OGL is also interesting as one of the few examples of a public copyright licence drafted by a private company rather than a government organisation, activist group or individual.
Next year the fifth edition of D&D will be released. The fourth edition of D&D wasn't released under the OGL, and is widely considered to have done more poorly than D&D third edition. Given there are current discussions about whether the fifth edition should come under the OGL, it seems appropriate to discuss whether the OGL is an open knowledge licence.
I already approached the FSF about having the OGL accepted as a free documentation license. A volunteer said that the FSF didn't have the resources to look at the OGL (which is fair enough) and pointed out that in his personal opinion the OGL's restriction on 'indicating compatibility' with other works would 'probably be considered a non-permissive, GPL-incompatible further restriction under section 7 of GPLv3 and perhaps also as a non-free restriction as well'. (See Section 7 of the OGL).
There are a few other things worth considering about the OGL:
- Whereas the Creative Commons licences make it clear that they do not remove any existing rights under copyright (like fair use, etc.), the OGL does not. In fact the OGL isn't explicitly a copyright licence at all, it just governs under what circumstances you can use certain text.
- Section 11 of the OGL says "You may not market or advertise the Open Game Content using the name of any Contributor unless You have written permission from the Contributor to do so." Even if you normally would be legally able to do so!
Someone I was talking to about this with on the free culture mailing list suggested that the OGL could be treated like the FDL: whether or not it counts as open knowledge depends on whether certain aspects of the licence are engaged. With the FDL, I believe that would be the invariant sections. With the OGL, that would be Product Identity.
My wiki has a page on the OGL which you might be interested in.
I would be very interested to hear your opinions on whether the OGL could be considered an open knowledge licence. I consider it a libre licence myself, but I can see that Sections 7 and 11 raise problems that might be unresolvable. It's a historically significant licence that's still in wide use today, so I think it's worth discussing.