I agree that the new Yahoo format is a step backward.
I noticed the following are problems created by the new format:
1) If you are researching a topic, it is no longer easy to follow a thread.
2) Threads can "vanish", although they are still there if you know where to look, but someone who asked a question and went on holiday for a week or two could go back to the site and not see a perfectly good reply to his/her question. You wouldn't even have a "clue" that a response had been provided. This does not apply if you get every single posting, every hour of the day. Maybe that's the point of this change-you WILL get every posting emailed to you or you won't access Yahoo.
3) Researching photos uploaded by a person known to be an expert on a certain subject is much more difficult than before. For a site with thousands of photos, it does not make sense to try to page though the photo albums.
There are solutions to these problems and I've found some of them, but even then, it's made the process painful.
Paul