  Music recommendation services collectively spin billions of songs for
millions of listeners on a daily basis. Users can typically listen to a variety
of songs tailored to their personal tastes and preferences. Music is not the
only type of content encountered in these services, however. Advertisements are
generally interspersed throughout the music stream to generate revenue for the
business. Additional content may include artist messaging, ticketing, sports,
news and weather. In this paper, we discuss issues that arise when multiple
content providers are stakeholders in the recommendation process. These
stakeholders each have their own objectives and must work in concert to sustain
a healthy music recommendation service.
