You fix one thing you break another. So it goes.
A month or two ago I updated the very old SQL database on my host to a newer version that would actually let me update wordpress (thus making it less prone to hacking). The process didn’t go as smoothly as I might have hoped and I introduced a bunch of ugly characters into things. Hand wave, unicode, mumble, mumble. I couldn’t figure out a terribly easy way to fix that, so I just exported the blog, did a series of search and replace on the resulting xml to clean up the mess, deleted all the posts, and imported the cleaned up xml file. This mostly seems to have worked. Except it deleted all the categories on all my posts. Presumably I could work out a way to fix up the xml file to keep that from happening and re-import it. More likely I’ll just slowly go back through and categorize posts. Sometimes computers (or possibly just the people who use them) are dumb.