Napster

Napster is a music and file sharing service that burst onto the Internet scene in a major way during the year 2000. Their technology allowed music fans to easily share MP3 format song files with each other, thus leading to massive copyright violations.

As of this writing (and much is surely still up in the air), Napster has lost a major legal battle and is seeking to settle the suit by offering to pay $1 billion out of their future profits.