When you go into a post, you'll be able to see the content of the
post and the first page of replies. Once you go into the second page of
replies, the page will change a bit. The original content will 'hide' and
you will only be able to see the replies. You can click on "+ Show Post" to see the original post again.
This will help the pages load quicker and you won't have to keep scrolling down to view replies.