Finally, random thought/question I just had: how hard would it be to add user-specific RSS feeds linked to the notification system? I check headlines by RSS, so I sometimes go days between visiting the site directly, depending on what comes up, which means I can go days without seeing the notifications about replies to me. So what I'm thinking is that being able to opt-into SN generating an RSS feed with a unique identifier (UUID or something similar) would be awesome. If you've messed with Reddit any, they do something like that and it's really convenient.
From comments.