When the invite-only, live-audio-chat app Clubhouse debuted in the spring of 2020, it was mostly an insular community for venture capitalists to talk about initial public offerings and return on investment. But over the last few months, as rappers, producers and music business executives flocked to it, Clubhouse became the central node for the hip-hop industry to talk shop, make connections and start flame wars. Stars like Meek Mill and 21 Savage will show up as guests among the regulars. Taste-making executives like Columbia Records’ Phylicia Fant, Top Dawg Entertainment’s Terrence “Punch” Henderson and Motown’s Ethiopia Habtemariam are members. Rising producers have had their lives changed by chance encounters with stars.