Potato is the first system for selling and reselling mp3 files. When you register at Potato and pay for a download, you also get a personal link, to place on your webpage. If someone buys a track from your webpage, you get a certain percentage but also the artist.
I hope I was able to explain it. Better read the the project homepage, which is in german and englisch. Potato is a cooperation between 4FO AG and the "Fraunhofer-Institut für Digitale Medientechnologie". "MP3" was also invented at the "Frauenhofer Institut".
