(In an upcoming patch, I'm considering making those face-containing icons clickable: The idea would be that when you click on it, it would open the topic, but with just your posts visible, so that you can easily see the things you've already said in that topic. Seems like an odd feature on its own, but, it's part of a bigger patch to allow quickly seeing only the posts within a topic by a specific author.)
I don't really see the benefit of doing that to be honest, unless you will be able to access this from the "Show latest posts from this user" page.
Maybe it's because I almost never check my updated topics for new replies, but what I have always found odd is that those icons with faces on them only go up to three pages for signifying that this topic has three or more pages.