Besides streaming (like a transmitter) what does the backboneServer do?

The backboneServer is the repository for all your music clips, text annotation and images. After building your playlist your station can be run automatically using standard rotation rules. The backboneServer, as your transmitter, also stores all the administrative information about your station such as audience size, when they were listening, the location from where they were listening and other critical information for your advertisers, underwriters and others who want to track the progress of your audience. Further, it provides the reports for you to file to the streaming authorities such as SoundExchange, BMI, ASCAP and Sesac.