For example.
This is a single post in your Readers Ride thread. Single Post
Now in the top right of that single post is another link (back to the parent thread)
So to use it as a bookmark, post in the url of that top right link.
BOOKMARK EXAMPLE
It's a bit longwinded but you could setup a list of significant bookmarks quite easily in the first post.
Ahh, yes, the top 'thread title' link.
Technically you could do that yourself, by url linking to the relevant post.
FOR EXAMPLE THIS IS POST NUMBER 1