This paper describes a research study about the effectiveness of Facebook, a social networking platform, as an organizational external communication medium. Based on DeLone & McLean’s (2004) information systems success model, a research model is proposed linking the “use of Facebook” and “perceived effectiveness of organizational external communication”. A survey instrument was developed to measure the perceptions of managers in charge of their organization’s social networks and external communication strategies. Forty-nine consumer facing firms participated in the study. The study found that there is a significant perception that Facebook is a tool contributing to the effectiveness of an organizational external communication. Estudio basado en el modelo de éxito SI DeLone&McLean(2004), plantea la relación entre el uso de Facebook y la efectividad de la comunicación externa. Se desarrolló un instrumento para medir la percepción de los encargados de redes sociales y comunicación externa de cuarenta-y-nueve empresas enfocadas en consumidores finales. Se encontró que existe una significativa percepción de que Facebook contribuye a la efectividad de la comunicación organizacional externa
