I'm really liking this threaded view of NN. I do have one very minor nit, though. The expand/collapse "button" seems to collapse a little too far. When expanded, a thread has a blank line between it and the thread below. But when you collapse it, that blank line is collpsed as well. I think it would look better to keep the blank line so that independent threads are still easily discernable.

Other than that, I think this view is great. Thanks for putting so much work into it.