UPDATE: We transitioned over to a new storage device and, after testing and making sure everything works correctly, opened back up at 9:00am EST. If you get a 404 error while visiting your site, logging in and republishing should fix it.
Although having a redundant storage device fail is highly unlikely, we'd still like to apologize for any inconvenience during the period you were unable to log-in and edit your pages. We feel really bad -- though on the upside, we've purchased a better array that should make file access quicker, which should speed up publishing and overall usage.
Our storage server (RAID array) was experiencing some issues earlier that would occasionally cause a 404 error when publishing your site. We're upgrading to a new device (should be completed by the end of the day) -- in the meantime, you can still edit your site, but you can't publish it until we fix the issue. Your site should still be available to the world as normal, without any issues.
If you happened to run into the 404 error and your site is currently unavailable, please email email@example.com, and we'll make sure your site gets back up ASAP.
We're very sorry for the inconvenience, and working hard to get over to the new storage device as soon as possible (should only be a couple hours left). Thanks for your patience while we deal with this infrastructure issue.