The program that practically led the file-sharing movement.
Napster was undoubtedly the greatest peer-to-peer program ever created, allowing millions of net users to download their favorite music at a price substantially smaller than the jacked up prices the RIAA makes us shell over. The price? Free.
Unfortunately, when someone decided to complain that they weren't getting $97 out of the millions they make every week, the RIAA decided to use that as an excuse to terminate Napster, thus forcing the legendary Shawn Fanning to turn the program into what is now the equivalent of O-Town: something we wish just died altogether.
Today there are some commendable file-sharing programs that, while doing their job, cannot match up to what Napster has brought to all of us.