Board Thread:General Discussion/@comment-168424-20130311222646/@comment-4811793-20130312165729

CC0 is a way of releasing content into the public domain by waiving all copyright restrictions for the work. To the best of my knowledge, there are no wikis on Wikia that are licensed in this way, and we would not allow that for new or existing wikis.

All text on Wikia is released under the CC-BY-SA, excpet on a few specifically defined wikis. It would not be possible to alter or add another layer of licensing more restrictive than that. As you do retain the copyright to your work, you can certainly announce your intentions not to pursue infringements, or otherwise make it clear that you would take a less restrictive approach, but you could not declare that while the wiki is CC-BY-SA, your contributions are really CC-BY-NC or under full copyright protection.