But what Napster did was to make it easy for Internet users anywhere to connect directly to one another and share files. The music doesn't reside at the Napster site. It sits on your PC and the PCs of millions of other Napster members. That's what makes such a service so impossible to police. Napster uses a central site to manage the users, but has no control over what they put on their PCs and what they decide to share with one another.
Individuals can name their files however they want.
So you can foil automated efforts to block the sharing of particular copyrighted material by just changing the spelling of names or adding a letter or number here and there. And while Napster is set up as a global system connecting tens of millions of people, the same technology can be used to link together much smaller, more focused communities of users. Another approach to P2P sharing known as Gnutella does the same thing without any central management of users. Gnutella client software is basically a mini search engine and a file serving system in one. That's pioneer-style sharing, like the early days of the Internet, with free and open software.