Good point, netmeg.
The only real difference is that my site is new (I bought the domain 11 months ago, and only started working on it within the last 6 months). The total number of inbound links doubled in about two days.
Given the domain age and the rapid link acquisition, I still think that *might* be the problem, but of course, the ranking drop very well may have nothing to do with anything that has changed.
I have noticed a few rankings popping back up to where they were previously, but in terms of visits I'm still only at about 50% of where I was a week ago.