A guy who ran the company who bought Daniel's startup later invested in the starting of Spotify. Their goal was to make a great music listening experience. The needed to have their site immediately start playing any music, without lag.
Spotify had always had a problem with record labels. Spotify wanted to provide the music for free and make money off ads. The music industry was vehemently opposed to this. Eventually, Daniel and co had to get one of the major labels to agree to license their music. The label got partial ownership of Spotify, and had a lot of guarantees that they would get paid, even if users listened to music for free.
Eventually Spotify had to compete with other music vendors like Apple and such. Spotify went public on the New York Stock Exchange. They offered shares directly to the public initially. The company was worth $20B, and eventually climbed as high as $50B. Daniel became a billionaire many times over.
