User blog comment:Kirkburn/Technical Update: September 2, 2015/@comment-13301-20150904094840/@comment-166269-20150905181406

@Ciencia Wikia does allow you to move your wikis; what it doesn't allow is the deletion or redirection of the Wikia copy. This is implicit in the CC license that all contributions are automatically released under: Wikia is free to continue making use of your and anyone else's contributions, for as long as they see fit, including continuing to host and serve them in their original form. Note also that the CC license is irrevocable: while you are free to relicense your contributions under any other license at any time, this does not apply to anyone currently using them under CC. And even if the license was revocable, while you may relicense your own contributions, you cannot relicense the contributions of any other editor, so Wikia would still be able to use those contributions.

Of course, if you were actually referring to some other way in which Wikia prevents you from moving your wikis, you should clarify for me. =)