I have an annoyed (but reasonably polite) message up on the Flickr Help Forums describing the problem. Whatever it is has happened since Dec. 15, when I posted my Weird West Fest report and the embedding worked just fine. What is all that "iframe" shit in what's supposed to be the HTML? If you feel like coming in and commenting on my forum post to the effect that you're having the same problem, it might cause them to pay a bit more attention.