Social media is an important platform to seek advice from its members. It is important to consider members of social media as trustworthy before one may seek advice. Reciprocity is a defining feature of social media. Trust propensity of a trustor is considered an important antecedent of trustworthiness and is cited more than 10,000 times. However, it is not clear how norm of reciprocity affects trustworthiness. This study asserts that Norm of reciprocity may be a more important antecedent of trustworthiness than trust propensity Partial least squares-structured equation modelling was used to model constructs. This study extends the Mayer’s model of trustworthiness. It has important implications for computer scientists and organization consultants working in area of trust in social media.