Some of the early free texture makers must be feeling bad right now, given the way textures are passed around in violation of the license, renamed, slightly modified, then resold or redistributed. Renderosity will have its hands full trying to verify that each new texture for sale here is not just a modification of some earlier free or commercial texture. Either that, or they can go the way of Turbosquid and just allow any blatant violation without checking first. It would have been easy to check things 5 or 6 years ago, but now that there are 10,000 or more vendors, just how much is derived from stuff where the originator is conveniently forgotten?