Great idea - I would love to see this implemented! The threaded view would make it a lot easier for me to scan through NN quickly and pick out the nodes that interest me, especially if it's been a while and there are a lot of intermingled listings in "notes".

One comment: unless I'm misunderstanding something, the size formatting reflects the age of the post only, so there is no way to tell which posts you've read. In addition, every time a post is added to a thread, all posts in that thread would be visible on the NN page, regardless of when you last clicked "I've checked all of these". Would it be possible to show just the root node and only the new replies (based on the "last checked" flag) under it? That would provide the organizational benefit of threading, while still retaining the filter provided by the "last checked" flag.

An alternative approach would be to format the titles based on the "last checked" flag, rather than based on the age of the node. For example, bold font could be used for new (unread) nodes, and those posted before the "last checked" flag could be normal/smaller. I think I like this idea better than the previous one, since I'd rather know if I've read a node than if the node is 1 vs 2 days old.

Finally, adding davido's suggestion regarding collapse/expand would give the ability to show all nodes between the root and newest nodes, thereby allowing the entire thread to be viewed.

Good work! Thanks again.