In this paper, we investigate whether and to what extent exposure to a company's social media activities over time is beneficial for corporate reputation, and whether conversational human voice mediates this relation. In a two-wave longitudinal survey among 1969 respondents, we assessed consumers' exposure to an international airline's social media activities, perceived level of conversational human voice and perception of corporate reputation. The results show that consumers' level of exposure to company social media activities precedes perceptions of corporate reputation. Also, conversational human voice mediates the relation between consumers' level of exposure to company social media activities and perceptions of corporate reputation. We discuss the implications of the results for the presence of organizations in social media.