The story and a link to
the solution can be found here, laced with tasty epithets.
Short version: Whenever you put a link in your LJ that goes to some e-commerce site (apparently about 150 are affected), Live Journal is redirecting those links through a third-party site. What this means, among other things, is that if you're linking to an e-commerce site from LJ with the hope of earning affiliate dollars, you'll lose them. Also, this third-party site doesn't always get the redirects right.
This doesn't affect me quite so much as it does others I know, which is the reason I'm posting this information here. I find it irritating and intrusive. I hope this info is of use to others.