Lemmy needs serverside hide features for posts and for communities or I’ll never find real interesting communities hiding on the 10th page of top feeds. This lack of functionality could cause the top feeds to stay trash permanently and drive away users. Especially when new apps are constantly appearing, client side hides are more or less useless as I switch between apps.
Reddit post hide features are fairly performant because they quietly expire after some period of time. They stay in your “hidden” list but actually will start showing in the results again if somehow that content is still visible. You can see this on super slow or abandoned subreddits if you hide every and come back a month later.
Reddit community blocking features have always sucked with the serverside limit of 100. Seems even more dire in Lemmy when the same shitposting communities spring up on different hosts
This feature already exists. When I block a community in an Android app and go to the website at sh.itjust.works, and look at my Preferences > Blocks, I see the community I just blocked in my app, even if they are on a remote instance.
So, I guess I don't understand the problem.