How often is the world map updated?

How long can it take before the terrain and buildings on a new island show up on the world map and on slurl.com?

And another question: is it really, really true that accounts that only own an island (deeded to a group in my case), without additional mainland, can be downgraded to basic accounts and save the monthly premium account fee? I read that a while ago, but wanted to be sure; I'm too afraid that my land is possibly annexed after downgrading

The map is currently hand set to run an update daily, but hopefully this will be an automated process soon. Because the world is so large, it cannot all be updated simultaneously so it's a rolling update.

Also, as an estate owner, you CAN revert to a basic account, but it's somewhat of a technicality. Your monthly fee will remain the same.