> Are the old servers being used as backups in the event Amazon has their very rare aws outage?
AWS is essentially acting as a backup of the old servers, as the datacenter is in danger of losing power.
That said, the cost, reliability, etc. had been carefully thought out, albeit as a somewhat longer-term project than it ended up being. More info will certainly wait at least until the current state of things is cleared up - Fogbugz and Kiln are still in the datacenter.
I know that's a lot of questions, but heck it would be an article I'd love to read and something I believe would be very relevant to the community as well!