One of the things that the recent addition of the Feeds feature highlighted was how many cross-posts / duplicate posts there are. When you display posts from linux@lemmy.world, linux@programming.dev, linux@lemmy.ml, etc all the cross-posts make it get repetitive, really fast. The same thing happens on the home feed too although it's a bit less obvious because there's a wider range of subjects involved.
Except now, it doesn't, because PieFed de-duplicates your feed! And your home page, and your topics. Attached to this post is a screenshot showing how it works out - an article posted to 7 different places is only shown once despite me having joined most of those communities.
We're still figuring out whether it's a good idea to merge all the comments from all the cross-posts into one page and how to do that in a way that respects the different culture/rules in the communities that the posts were made in. It's a tricky UX and social question.
I've held off on adding a cross-post function to PieFed until now but it'll be added soon.
I think instance-specific rules are largely ignored anyway - we don't really check the home. Instance of communities and go there to read their rules before posting. If it's clear which community you're posting to and the rules of that community are visible, I'd say that's plenty. :)