At its peak, Napster was perhaps the most popular Web site ever created. In less than a year, it went from zero to 60 million visitors per month. Then it was shut down by a court order because of copyright violations, and wouldn't relaunch until 2003 as a legal music-download site.

The original Napster became so popular so quickly because it offered a unique product -- free music that you could obtain nearly effortlessly from a gigantic database. You no longer had to go to the music store to get music. You no longer had to pay for it. You no longer had to worry about cueing up a CD and finding a cassette to record it onto. And nearly every song in the universe was available.

Given that it was distributing an illegal product, the original Napster's key weakness lay in its architecture -- the way that the creators designed the system. When the courts decided that Napster was promoting copyright infringement, it was very easy for a court order to shut the site down.

The fact that Napster promoted copyright violations did not matter to its users. Most of them have turned to a new file-sharing architecture known as Gnutella. In this article, you will learn about the differences between Gnutella and the old Napster that allow Gnutella to survive today despite a hostile legal environment.