I've noticed that there are RSS feeds associated to a given question, but unless my copy of Firefox is malfunctioning, I haven't seen a similar feed that would tell us e.g. about the latest unanswered questions.
The same observation actually applies to [Stack|Math]Overflow, so are these unavailable, or disabled by default, or completely uninteresting? I'm probably too addicted to this website anyway to avoid visiting it for a long period of time, but still, I'm under the impression that such feeds would be valuable.