Bluesky is the first app built on the ATProtocol, its protocol for federation, sort of like how Mastodon was among the first to use ActivityPub after the overcomplexity of OStatus. The ATProtocol is a few years younger than ActivityPub, so its landscape isn’t fleshed out yet. Currently Bluesky caters more towards creators, artists, and social togetherness, whereas ActivityPub tends to lean harder into attracting techies. Both protocols can be run as independent instances, but most people are still using bsky.social for now until more instances pop up and federate together. The process for hosting a Bluesky instance is still undergoing development, but all features of it have been opened up. There exist multiple bridge systems that can interweave ActivityPub with ATProto.
https://github.com/bluesky-social/pds
https://whtwnd.com/bnewbold.net/entries/Notes on Running a Full-Network atproto Relay (July 2024)
A quick scroll of his account on Bluesky ( https://bsky.app/profile/urlyman.mastodon.social.ap.brid.gy ) makes it pretty clear why his Discover sucks. The algorithm on Bluesky sorta works like a mirror, you get out what you put in. My feed is all art posts and wholesome memes because I follow artists, creators, and comic pages, so it sounds like he’s trained his algorithm to be full of political complaining and toxic people like him. He should probably look into the Mute Words feature and start blocking stuff he thinks is toxic!