Awesome work! I really like the new "Mentions" tab, especially as it differentiates between "posts" and "comments".
Might you do something similar for the "Replies" tab?
The use case: often, when people reply to one of my posts, it's a few-word comment like "nice post" and it's not quite as important that I read and reply to those.
Versus, when I comment on someone else's post, I very much want to know about replies to that so that I can continue a discussion.
So, "replies to my comments" should be significantly higher in my priorities than "replies to my posts" -- meaning, it would be great to have an interface into each.