Admins can sticky/unsticky topics. This causes them to be coloured green in the topic listing.
only show stickied topics in the group they were posted in, not the front page
put stickied topics at top of groups
rename them to "pinned" topics? (while "sticky" is familiar to Reddit users, I think "pinned" is easier to understand)
oh also I forgot to make the alembic revision file oops