Napster’s shutdown helped inspire Daniel Ek’s idea for Spotify. The collapse of the pioneering peer-to-peer music service made Ek think about how digital music could be offered legally and conveniently.
Napster became famous around the turn of the millennium by letting users exchange music files directly with one another. Its service was ultimately closed after major copyright litigation, but file-sharing continued through other platforms, including Kazaa. Ek later described this environment as evidence that legislation alone could not eliminate piracy.
His proposed answer was a service that would be easier and more attractive than illegal downloading while compensating the music industry. That idea became Spotify, which Ek co-founded with Martin Lorentzon in Stockholm in 2006. Spotify launched its legal streaming service in 2008.
Grokster, Gnutella, and LimeWire were also associated with peer-to-peer file sharing, but they are not the service identified in the account of Ek’s inspiration. Napster is the canonical answer because its shutdown is explicitly tied to the origin story of Spotify.