The continuing popularity and adoption of social media by general public users and the realisation of its potential customer engagement power by business, is highlighting the importance of social media to ongoing business activities and strategies. However, current research that is more focused around getting the best out of social media, generates little debate of the adoption factors driving public use of social media as a communication medium. Even though businesses have an opportunity to broaden their reach by adding social media to the communication strategic-mix, the dearth of informed discussions relating to theoretical underpinnings associated with the public adaptation of social media as a communication medium fails to clearly inform strategic business decisions regarding adoption decision-making. This research study conducted in the Australian context queries established theoretical frameworks by asking the question; what theoretical foundations do influence the social media adoption by intended audience of communication?