The founders of Napster probably weren’t thinking about communism in 1999 when they made peer-to-peer sharing of digital audio files possible. But in doing so, they undermined one of the core elements of capitalism: scarcity. Without scarcity, prices drop to zero and markets stop working. So when people started duplicating and sharing songs for free, they destroyed the business model of record companies, one download at a time. Eventually, Napster was shut down by legal threats.