In the last month or so, we’ve steadily accumulated so many daily visitors that our server setup just isn’t up to the task of dealing with all of them any more. This is why you’re seeing database errors so frequently.
Tomorrow (March 7 2012) we’ll be taking the website offline while we migrate to new servers with our friends at Mythic Beasts. The exact time that’ll happen depends on what Pete’s schedule looks like, but we hope the downtime won’t last for more than a couple of hours. Make the most of those database error messages now, because once we come back up again, you shouldn’t ever have to look at one again (at least on this website).