Oh! I was also wondering! Do "the person/people that update the worlds" update them after the world has been "ripped to shreds" so to speak?
Periodically XD It is really somewhat random, I'm pretty sure that Justin and Co. do it when they're in the mood. But needless to say, don't start a massive, important creation there, because it will most likely be lost, both to griefing and/or reset.