How could this site be improved?
My top three things would be:
1. Keep all the notifications for a single post together. It's kind of insane to get a line of eight comment notifications for the same post instead of it being condensed and just being shown +8 on the same post.
2. The ability to turn off updates from discussions you no longer want to be a part of. (It very well may be a feature, just one that's not very obvious.)
3. Getting notified about comments that aren't replies to your own on a post you're a part of so you can continue to be more involved in the discussion.