Bookwyrm is a Fediverse alternative to Goodreads. :)

I didn't see you were on a different instance - each community needs to be manually added to your instance's federation list. Lemmy doesn't federate the entire instance - just individual communities. You only see communities that have at least 1 subscriber local to your instance - no subscribers, no federation.

If you go to dmv.social in a web browser and you type https://kbin.social/m/wizardposting into the search bar on your instance, you'll see it pop up in the search. Then you can subscribe to it on your instance and the community will start federating because there's 1 subscriber on your instance (you). You won't see any past posts from before federation, but you'll see future ones.

They work fine on the actual Lemmy.world website as well as in Sync for Lemmy. Might be a bug with Memmy.