I received a new note that it seems feedback (commenting) on my blog is disabled, so as I wasn't able to fall asleep I set out to track down the cause. After taking a look at the files in detail, it seems the script powering the feedback function was deliberately renamed by - I assume - my host. I'll be contacting them later today or tomorrow, especially since I had replied to their "server move message" and I've got several anti-spam measures installed to prevent abuse.
I'm not pleased at all, and honestly am rather surprised with them taking this kind of measure without informing me.
Thanks for the report, Ash!