I've turned off quick links for everybody, as I'm more and more certain that it's strategic combinations of old-time, non-forum-marking-read people hitting the index page that's causing our mysql to end up stacking up.
FYI/FWIW, I haven't seen any of the oddities since you made that change. Seems like a reasonable theory to me! Thanks.
If you gaze deeply into the names of the people online, you may notice that if they are in the process of starting a new thread or leaving a new reply, their name will appear red (or black) on white background.