Internet radio became an industry off the radar of the major labels, starting with no rules and constricting over time. The environment has thus far allowed for the growth of sites like Pandora and Last.fm. source
For years, record companies, songwriters and publishers wanted their fair share. Unfortunately, that fair share was so high that it threatened to kill sites like Pandora. Enter stalemate. source
Today, Pandora and SoundExchange agreed to 40-50% lower rates which will allow Pandora and others to keep operating. The rates are still higher than the FM dial, but they can live with them. source