Here's how you get things like astolat:
<user name=astolat site=archiveofourown.org>
Here's how you do a read more:
<cut text="read more">
Hover your cursor over the little "person" icon next to their name (like in this: astolat) and a little menu will appear with "subscribe" and "grant access" and you can click it and it will add the person without having to load a separate page or click twice.
tenlittlebullets's post reminded me: if you are surfing a prompt meme where people leave prompts in comments, then if it is a paid account (you can gift paid time to a community if it isn't) you can search the comments using search (the search link will be on the community profile):
(If you buy paid time for a big community it will take a little bit before the whole community gets searchable, but then eg you can search for your favorite pairing or character or kink only.)
You can also read this entry on Dreamwidth ( comments)