Not sure when it happened, but I really like the feature where if you're reading a thread and then use the "back" button, it will be marked as read when you get back to the forum page.
One thing I wonder about: Say I am reading a thread, then I go to another thread, and by the time I'm done reading the second one, there's a few new posts in the first thread. If I click the "Go to first new post" button, it will take me to the same post as when I read it the first time, not the new posts that have been up since I finished. I'm not great at explaining, does that make sense? Anyway, is there a way to go to the posts put up since I last read it?