There should be a page which lists the submissions that have recently been commented on. Otherwise, it's essentially meaningless to make thoughtful comments on old threads. Having a *hide* option would be welcome too.

there is a prototype of this at news.ycombinator.com/active

That works well. A listing of the most active is better than a listing of recently commented on. What's the threshold for most active?

For the time being, I'd settle for just converting newlines to br's. Adding hyperlinks before there's solid infrastructure for dealing with spam would be a mistake. I'll be surprised if more than few days go by before spam shows up, even without hyperlinks.

Spam actually showed up the first day. Fortunately we already had good tools for dealing with it.

What type of spam do you get and how do you handle it?

done; we now have all three of these