[1] http://webcache.googleusercontent.com/search?q=cache:lHEK939...
[1] http://webcache.googleusercontent.com/search?q=cache:lHEK939...
My guess is that the second data centre was there, but failover didn't work for some reason. It would be good to know the reason, though.
[1] http://www.joelonsoftware.com/items/2007/07/09.html
Edit: Politeness
I think your guess is probably wrong though, in a status post 2 days ago they listed[1] the precautions they were taking so that they could be "confident that all of our services will remain available to our customers throughout the weather", and they did not refer to another data center, only "Our data center". That would be the ideal place to mention any fall-back centre.
They are also resolutely not replying to public posts on various boards questioning these issues. I am cutting them some slack in that they have a lot to attend to right now, although the fact they are managing to find time to reply to some threads (like the one in which this is posted) is a tad sniffy.
Once they're back up and running I'm sure they'll update us all on why their redundancy failed or magically wasn't there.
[1] http://status.fogcreek.com/2012/10/feelin-fine-no-expected-d...
However, as I understand from your profile you are a coder on Kiln[1]. Are you really telling us you don't know whether there was a backup datacenter or not?
If there was, I understand you might not be able to tell us why it didn't catch the fail-over, or if not, why there wasn't one in the first place. However basic info like whether a backup existed in the first place really seems like it should be within your realm of knowledge.
Re their status posts: you may well be right. Time will tell I guess.