Businesses could sustain their market presence at traditional brick and mortar or through the Internet by facilitating and encouraging the public to pass along a marketing message known as viral marketing. Nonetheless, it should be conducted in ethical manner to disseminate credible and trusted message content among both parties. This study aims to analyse the influence of some pre-defined factors (namely, playfulness, critical mass, community driven, and peer pressure) in customer satisfaction in the context of the use of viral marketing in social media. For this purpose, 200 respondents were randomly drawn from among students at a public university in the Federal Territory of Labuan, Malaysia. A questionnaire was implemented and the results were analyzed using multiple regression analysis. Results revealed that critical mass stood out as the most the important predictor of customer satisfaction with viral marketing via SNS, followed by playfulness. Meanwhile, social network website with high level of critical mass has more influence on potential users to believe and participate in viral marketing activity. Conclusion and recommendations for future study are also discussed.