I love how we're using Hacker News here -- this is definitely not what it was designed for. What we're really doing is something like a live chat room while watching a common talk, but unlike chat rooms it can be threaded and points can be allocated. Also unlike a chat room, HN does not automatically update when we get new discussion messages, but that's a constraint of the technologies at the time it was built.

It might be very interesting to try to use comet-casting or websockets to revolutionize chat in precisely that way, realtime threaded discussions. So, in addition to all of the chat constraints you have the ability to dynamically mark certain chat messages as replying to other messages, and as the noise in the chat room gets higher you can filter yourself to just "I want to follow this discussion."