Hans Passant quotes from the CC-Wiki license:
I think there's a problem here. The full text of the Creative Commons License under which SOIS publishes your answer has this clause in section 7b, Termination:
Subject to the above terms and conditions, the license granted here is perpetual (for the duration of the applicable copyright in the Work). Notwithstanding the above, Licensor reserves the right to release the Work under different license terms or to stop distributing the Work at any time; provided, however that any such election will not serve to withdraw this License (or any other license that has been, or is required to be, granted under the terms of this License), and this License will continue in full force and effect unless terminated as stated above.
I however don't have a clue what the provided part of the sentence tries to say.
My interpretation is that this is not the case, and that "stop distributing the Work" means distributing it elsewhere. In my understanding, the license granted to SO is for all eternity, and not unilaterally revocable. I have no idea whether this is correct, though.