Online interpersonal interaction and communication has become an important aspect of social activities, especially among Millennials (young adults). However, the African continent has the lowest Internet access across the globe, but the development and rapid adoption of mobile technology has led to a major increase in the usage of Internet and new online Information and Communications Technology (ICT) channels, which are collectively referred to as social media. Social media platforms have become an integral part of everyday life and marketing communications via these digital channels has become one of the latest trends in South Africa (SA). The most commonly used social medium in the world is Facebook, whereas Mxit is the largest locally established online ICT conduit. However, not much is known about Millennials’ attitudes towards social media as an advertising medium. Therefore, several surveys were used to investigate the effect of social media (Facebook and Mxit) marketing communications have on each of the hierarchy response model attitude stages among Millennials in SA. The results confirm that social media marketing communications have a significant influence on all of the hierarchy response model attitude stages, but on a declining degree as South African Millennials progress to the higher stages. Furthermore, the findings also reveal that several online usage and demographic characteristics have a significant influence on attitudes towards these new interactive ICT conduits.