Shortly after the Apple e-mail I received, I got this message from my host, Liberated Syndication:
Ok, like almost everyone of our users have emailed us about the recent flush of iTunes emails. Please keep an eye on http://support.libsyn.com for the latest on this.
It looks like there was a combination of events today that have compounded. The iTunes change is just one of the things going on. We're not putting all the blame on it, but it's been hard to diagnose. The important message is we are working on our end of it and have a line of communication to the Apple guys.
Thank you for your patience and understanding.