You may remember this from the end of November, way back in 2012:
I discovered that every last post — 12,700 of them — had been sheared of its category and tag information. Worse yet, the View All Posts function in the WordPress admin showed no posts to view. Despite this, permalinks were working and comments were being posted.
When it happened again, I literally cut and pasted my first support ticket into a new one. The problem was readdressed, but the tech suggested that if it continued to recur, I should consider moving to a server with more space, inasmuch as I’m running six sites off this account. After thinking this over for about 3.5 CPU cycles, I requested such a move, which was completed that evening. I have no reason to think readers will be affected by this, but if you see something acting sillier than usual (besides me), please let me know.