Controversial taboo appeals as an executional cue in viral advertising have commonly been used by advertisers. In this context, the study investigates the role of medium context on the effectiveness of controversial taboo ads. By implementing a tightly controlled experiment which deals with controversial taboo ads embedded in a press article and in a viral context, the study finds that the viral medium context does not lead to a more positive attitude toward the embedded brand or to more positive purchase intentions. In addition, a viral medium context triggers ‘unintended consequences’ that lead consumers to undermine the level of tabooness of the viral advertising and subjective norms. To increase the external validity of the research, the results were replicated for two kinds of controversial taboo appeals; one related to sexuality, and the other to death. The results provide useful implications for theory and practice. Extending viral advertising research, a different angle on controversial viral advertising has been taken, shifting from an advertiser and brand focus, to a societal and social one. The work leads to a better understanding of the ethics of controversial viral advertising, and demonstrates its role in the trivialization of taboo behaviors and imagery. The results confirm the need for more regulation of online buzz communication and encourage regulatory bodies to extend policies of viral advertising regulation.