As with this s9y site, there should be the opportunity for a person to "subscribe" to the post, so that they are eMailed and advised of new comments.
Plus they are usually in date/time order, so it is not that hard for someone to pick up on comments on any particular post where they last left off.
I initially used the Disqus plug in, but then actually inbuilt Disqus natively, so that members of my site can use Disqus using their site Membership Log-in without having to log in twice to comment, or they can use their Facebook, Twitter, Google+ or actual Disqus accounts to log-in.
You can see how it looks on this page: http://mybusiness-mylife.com/global/pr/blog.php?/archives/2-Special-Announcement-Coming-Soon!.php
You can see at the bottom left of the Disqus comment area Disqus has a link to allow you to subscribe to the post and receive updates.
Within the Clean Blog Page Options there is a "Yes/No" Option to "Show link to entry's comments".
I have mine set to "No" because I am happy with what I have.
There is no "Help" button for this function but either Don may explain how it works, or probably a bit of trial and error may give you an idea.