I also noticed that none of the forum sections had the "new post" graphic despite KDR's post above being a clearly new post since I was last on.
I don't have the NEW graphic on the main page but when I open a forum it shows which topics have NEW posts. Weird.
Ditto. I'm using Firefox 3.0.6 and the non-casual theme. I even tried logging out and back in, then logging out and deleting cookies, after which I couldn't log in for a few minutes. I was told my login was wrong and then just got a "Maintenance mode" message. It's still not showing the new message graphic on the main page.
Surprise Twist (or not): Clicking the icon by the forum name still correctly returns just the new posts.