If one thing’s clear from the discussion about the new Wizards license for D&D Fourth Edition, it’s that people like to spout off on the subject without knowing what the heck the OGL says, what the difference is between the OGL and d20 STL, and what an “open” license is in the first place. So here’s a convenient summary if you want to know what all of this means. Read and understand – personally, I don’t mind differing opinions, but I do mind ignorant opinions.
Open Gaming License (OGL): A license written by Wizards of the Coast to be a generic “open” license suitable for RPGs. WotC released most of the core 3e and then 3.5e D&D rules under the OGL. Many other gaming companies have published OGL games – some partly based on D&D OGL content, some completely original and unrelated to the D&D rules.
The official OGL v1.0a: http://www.wizards.com/d20/files/OGLv1.0a.rtf
Open Gaming Content (OGC): This is content designated as “open” according to the OGL in a given work which has been released under the OGL. In a given work, you can specify certain parts as OGC and other parts as closed; see Product Identity below.
Product Identity (PI): Parts of a work released under the OGL that are designated as NOT open. Most commonly, this is applied to art, character names, trade dress, and other such proprietary intellectual property, but it can be applied to bits of rules. For example, Wizards of the Coast made a SRD (see below) containing most of the rules found in the D&D Player’s Handbook, albeit restated and stripped of trademark/trade dress information, open EXCEPT for ability score generation methods and experience point/level tables.
Open License: What is an “open” license? A license anyone can pick up and use? No. A royalty-free license? Only in part. A license surrounding published content is free if it is royalty free and share alike. “Share alike” means that openly shared content can be reused and built upon in other works, but you have to distribute the resulting product similarly under an open license. The OGL is one particular open license and part of the overall historical development of “open gaming“.
d20 System Trademark License (d20 STL): A license from Wizards to control and allow people to publish products that indicate d20 compliance specifically. It’s more restrictive (decency clauses, revocable at WotC’s discretion) and not open but allows use of the d20 logo on products to indicate D&D compatibility. Many third party D&D adventures and other products are published under the d20 STL.
The official d20 STL: http://www.wizards.com/d20/files/d20stlv6.rtf
System Reference Document (SRD): SRD is not a term contained in the OGL. It’s a term people use to indicate a convenient summary of open content for a game system. A SRD may be put together by the company whose game it is or by anyone else; as it’s open content there’s no restriction on that. There’s no guarantee that a SRD, whether game company or fan-compiled, is complete, correct, or updated with new OGC as it becomes available. The OGC in OGL works themselves are the true “source.”
The official d20 OGL SRD:
An example of another OGL SRD, Spirit of the Century:
A list of many various extant SRDs:
New for D&D fourth edition, Wizards has announced:
Dungeons & Dragons 4E Game System License (D&D 4E GSL): a new, not yet unveiled license to allow third party (company and individual) support of D&D 4e. Discussion of this new license on the ENWorld forums by people including WotC’s Licensing Manager and D&D Brand Manager indicates that the D&D 4E GSL likely has a “poison pill” provision that states a person or company who wishes to produce 4e-compatible content under the GSL may not also publish any open gaming content under the OGL.
d20 Game System License (d20 GSL): a new, not yet unveiled license to allow third party creation of RPG products in non-fantasy settings with the 4E rules.