There seems to be a big delay for a large portion of the messages that go to yahoo.com addresses. I've been seeing notices of messages that are delayed up to 72 hours. Unfortunately, I believe that it's a problem on the yahoo side since other messages from the site seem to be getting through okay. I did a few test messages to my non-yahoo address and they went through.
I'm not sure it will help, but you might try adding mods@absolutechaos.net to your address book and see if that will help it get through their spam filter (not sure that it will, but worth a shot...?)