Pandora needs to be able to recognize the topic or theme of a song and be able to add or remove songs from a station that fit that theme. For example, if I wanted to create a date night station and wanted pandora to only include songs that had romantic or love themes. Or I wanted a grief station that included songs about faith, resurrection, the passing of family or friends, memories of family/friends. Or maybe I wanted a party station with songs about hanging out, spending time with friends, etc.