Board Thread:General Discussion/@comment-168424-20130311222646/@comment-117877-20141112001935

But what PedroM asked about CC0... Can somebody except the CC-BY-SA 3.0/4.0 add an extra layer of copyright waiver that is even more free than CC-BY-SA, ie CC-BY and CC0-1.0-Universal? In this example I'm asking about the wiki creator chooses to license the wiki under CC-BY-SA 4.0 and CC-BY 4.0 and waive it under CC0-1.0-Universal. In that case, are all contributors to that wiki licensing under CC-BY-SA 4.0 and CC-BY 4.0 and also waiving their copyright under CC0-1.0-Universal? Can the contributors individually choose not to waive their copyright under CC0-1.0-Universal?