Requiring public domain is a bad idea. Suppose I take a bunch of photographs of serene mountaintop horizons for use in crafting sky spheres or distant landscape spheres, and I post them into the public domain on the texture website. Later, I decide I want to build a portfolio of my work so that I can get hired as a freelance professional photographer. Someone sees that I'm using photos that were released into the public domain, so they download my photos, put them on their site, and claim that they're in their portfolio.
At that point, I have absolutely no recourse available to me. That other person can claim that they took the photos, sell the photos, and generally do as they please, because they were released into the public domain.
Such an arrangement would substantially discourage people from submitting their content to the effort. In fact, this has already come up in discussion
elsewhere in terms of Cyan being allowed to redistribute user-created music to MORE players. My answer over there was to look at YouTube as an example: when you submit to YouTube, you keep the copyright of your work, but you grant a license to ensure that everyone's in the clear when it comes to downloading your stuff from them.
So, I recommend crafting a license agreement, running it by Cyan's legal eagles, and then requiring that all submitters agree to license the submitted work via that license agreement. If you want, give them the public domain option, but don't require it.
The license would have to include features such as (and I don't intend this to be a necessarily complete list):
- The submitter grants Cyan Worlds, Inc. a perpetual, royalty-free, and non-exclusive license to store, copy, and redistribute the submitted content and to create, store, copy, and redistribute derivative works based upon said content for the purposes of delivering said content and said derivative works to users of their online computer game MORE.
- The submitter grants The Guild of Writers {or insert preferred entity controlling the texture site here} a perpetual, royalty-free, and non-exclusive license to store, copy, and redistribute the submitted content and to store, copy, and redistribute derivative works based upon said content to any person who has accepted the terms of this license agreement, for the purpose of collaborative development of user-created game content for Cyan Worlds's online computer game MORE.
- The submitter grants any individual accepting the terms of the license a perpetual, royalty-free, and non-exclusive license to store and copy the submitted content and to create, store, and copy derivative works based upon said content for the purposes of developing user-created game content for Cyan Worlds's online computer game MORE.
- The submitter grants any individual accepting the terms of the license a perpetual, royalty-free, and non-exclusive license to redistribute the submitted content and to redistribute derivative works based upon said content to any other person who has accepted the terms of this license agreement, for the purpose of collaborative development of user-created game content for Cyan Worlds's online computer game MORE.
- The submitter grants any individual accepting the terms of the license a perpetual, royalty-free, and non-exclusive license to redistribute the submitted content and to redistribute derivative works based upon said content to Cyan Worlds, Inc., for the purpose of delivering user-created game content for Cyan Worlds's online computer game MORE.
- An individual accepting the terms of this license agrees not to use the submitted content in any fashion outside the scope of the development of user-created game content for Cyan Worlds's online computer game MORE, publicity campaigns for said game, and private personal use. Said individual agrees not to use said content in any fashion outside the terms of the granted license and/or any rights granted by law.
- This agreement is not a transfer or assignment of copyright.
I think that covers it, but folks might want to see if I've left anything out. It would probably need some cleanup as well, as my legalese-fu isn't all that great (too many patents, not enough license agreements - plus, I'm not a lawyer!). The point here is to require people to license their work for free use within the scope of MORE, but to let them keep their rights substantially when it comes to other outside uses.