Sounds like a form of social proof combined with low friction following? Authors say it creates a "rich get richer" dynamic. Also I wonder if there's a long-term risk that it creates a "everyone follows the same people" effect which may decrease delight, plus decrease chance of random jackpot posts that come out of nowhere and hook everyone for a day. If I've diagnosed correctly then I'm sure that Bluesky has figured out answers to these but I'm not sure how.