A quick heads up, folks, that you can now chose to get an email notification whenever someone replies to one of your comments. It's opt-in — look for the box on posts starting now — so you control just how spammy things get. If things get out of control, just hit the "disable" link that'll be in the notification email.
Right now this is only enabled on the traditional web side of things. We'll get it added into the app just as soon as we can.
And, yes, we still have big plans ahead for notifications, beyond just simple emails. Thanks for your patience on that as we continue to spruce things up around here.