This research analyzes Social Network Service(SNS) user responses to the TV dance program “Dancing 9” and discusses its success factors. To this end, comment data registered on YouTube Dancing 9 videos were collected and analyzed for word frequency and topic modeling. Topical modeling resulted in six topics: Discovery of Star Dancer, Competition Structure, Street Dancer, Sympathy for Dance, Gatekeeping, and Music Effects. Based on these topics, a discussion of Dancing 9’s success factors included: the discovery and production of star dancers, the competition structure of the Red Wings versus Blue Eye teams, convergence and harmony between different dance genres, dance skills with both popularity and artistry, gatekeeping elements that create dramatic tension, and the harmony of music and dance that meet the standards of the public. Based on these success factors, later-produced TV dance programs should identify public tastes and work harder to spread the dance.