Slashdot has an article from the linked to the BBC about a devastating security situation this morning:
Flight Simulator community website Avsim has experienced a total data loss after both of their online servers were hacked. The site's founder, Tom Allensworth, explained why 13 years of community developed terrains, skins, and mods will not be restored from backups: 'Some have asked whether or not we had back ups. Yes, we dutifully backed up our servers every day. Unfortunately, we backed up the servers between our two servers. The hacker took out both servers, destroying our ability to use one or the other back up to remedy the situation.'
Best practices dictated Always have off site backups (preferably in another city). Maybe that's not even enough. Offline backups would have helped here too.
No word yet on the how the hacker gained access.