So, similar to the current/old boards where on the left hand navigation there is a module for Favorites where forums can be bookmarked. This allows one to navigate between forums without the quick nav at the bottom of posts and is not a subscription feature. I believe this is what Karassa was...
So, how do you tell if a thread has new posts or not? I've seen the forum icon turn from gray to blue and back to gray, but not a similar indicator for threads.
When I select Forum Actions -> Mark forums read the forums still have lil green checkmarks (which I've taken to mean new posts.)
Quasi related, orange post thingies remain orange after going into said thread and after doing the mark forums read.