What change did Napster effectively turn a club good into?

Napster effectively transformed a club good into a public good. A club good is characterized by being excludable and non-rivalrous, meaning that access can be restricted to certain individuals (like members of a club) and one person using the good does not diminish its availability to others. Music files on Napster were initially shared among a specific group of users who subscribed to the service, making it a club good.

However, with Napster’s file-sharing capabilities, music became easily accessible to anyone with an internet connection, eliminating the exclusion aspect of the club good. This wide availability meant that one person's use of a song did not reduce the availability of that song for others, fitting the definition of a public good. Public goods are non-excludable and non-rivalrous, allowing everyone to benefit from them without diminishing their value or availability. Thus, Napster’s effect on music distribution exemplifies how a club good transitioned into a public good, changing the dynamics of accessibility and sharing in the digital age.