It's a little different than bookmarks, though, Will. When I bookmark a thread, it means I want to see it whether or not I've ever posted in it. Like stories others are writing that I'm watching. Yes, I do sometimes follow other people's stories or discussions without being part of them!
When I hit "Show New Replies to My Posts" I get several replies that I don't need to read every time, but also several threads I do want to read. I used to post in "What are you drinking" a lot. But haven't for a while, and don't always want to look at it. I'd love to just click a button to say hide that one, thanks. I could then click on the threads I don't feel like reading at the moment and tend to the ones I do. I look at the new replies thread several times a day to continue various conversations.