Okay so what the heck happened to the site on Thursday night?
It all boiled down to running out of storage quota on my server. My server account had crept over its quota limit without me knowing. Things were still working like this, but since WordPress 2.8 (the software that runs this website) came out on Thursday I ran the upgrade, and then we hit problems.
Anyway, lots of technical details later storage quota was extended and the site was put back as it was, and subsequently upgrade to WP 2.8.
Why am I telling you all this? Well the moral of the story is that no matter what you’re doing – keep backups of everything you do! Had I not had backups of this site, it would be trashed now. Moreover, had my backups been better organised, the site would have been up several hours sooner.
I’ve now improved my file backup procedures to be automatic so they’re always up to date. Fortunately, I was already using a WordPress plugin which e-mailed me a daily backup of my database.
Make sure you keep your stuff backed up too.