We apologize for the down time. We're still not quite sure what the status of things is with our host, Rackspace (we're on the "Rackspace Cloud"). We know they are having some issues, and apparently while not the source of the issues, our site was one of several sites that is/was compounding the problem significantly.
So, they shut us, along with several other sites off, so as not to crash the entire "cloud."
For us, and our readers it was an unfortunate outcome that had us out of commission for at least 5 hours and as of this writing there are certain things we still need to resolve, like why our site was/is putting such a high load on their storage devices (AKA hard drives).
For us it is very frustrating because we've made no recent changes in terms of how the site operates (other than normal upgrading of the WordPress software) and are not sure whether we had always been putting high load on their storage devices but it's only just now a problem for Rackspace, or whether something changed.
Unfortunately for now, there are as many questions as there are answers.
We're doing our best to get to the bottom of it, and we're really sorry about the downtime.