This isn't anything major but I wonder what would happen if when a new thread is added it be added to the top instead of the bottom where if there are several choices it might not get viewed while older threads in a story have already got several views and probably bookmarked. Just a thought to add a bit of randomness to a story.
I think it would be a good idea if you had sort options. Like it defaults to chronological order but you could have it to newest first.
I would think it should be marked somehow (perhaps named aside the chapters where the date for latest update is given), but positioned wherever it belongs in the story.