That would mean you've already read them. If you click Recent Posts, you'll see all of them. If you click New Posts, you'll see threads with posts you haven't read yet.Well, when I hit 'New Posts' they never showed your post or any other post under this thread.
Stranger
Give it a try. Click "New Posts" before you read this post, and it will show as a new post, since you won't have read it yet.