Web 2.0-based cultural diffusion occurs not only through viral word-of-mouth communication but also through Internet memes in which cultural consumers review, resemble, and recreate old cultural components, resulting in the creation of new cultural forms. YouTube features a platform for memetic creation with a host of user-generated parodies, reviews, and mashups derived from viral videos. This study examines the cultural ecosystem of YouTube memes inspired by Korean artist Psy’s viral production “Gangnam Style.” The study focuses on the salience of various genres of YouTube memes and structural connections between memetic videos. According to the results, the viral video of “Gangnam Style” sparked a sizable amount of user creativity, including remixes, parodies, self-directed performances, and reviews, among others. A network analysis of connections between memetic videos shows that various memetic genres drew different levels of audience attention and actions across various stages of the 3-month-long diffusion process. In addition, the content of the traditional mass media played a key role in giving the viral video wider publicity and acknowledgement, but this role was later shared by user-generated content.