No need to post a link to the Google cache. The original source [1] contains the same text. I don't think that there is much risk that they might ninja-edit the five year-old announcement to change the claim about redundancy.
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.
Apologies, the link was copied from an unrelated post elsewhere and I didn't really look at the URL, no slight of hand was expected by them.
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.
Just so we're clear, I have time to reply to these because I'm stranded in LA. That's also why I have to go back and edit my posts fairly regularly when I get better information out of NY. Pretty much everyone in NYC, such as the ops team, who could answer your questions, is very much not here right now. That's why you're getting odd silences: I'm happy to answer things I know or am involved with, but not to speculate.
I appreciate that you don't have all of the info on whats happening, and that those who do are a tad busy right now.
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.
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