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.
As I've noted before, we lost a lot of Google juju around Columbus Day 2008 but did get some portion of it back around June 19th. So there's a lot of repeat action but amongst the new entries, mostly stuff started in the second half of the year.