Purpose -- This study focuses on managers' perceptions of employees' communicative role in social media, and explores the changes in the contractual nature of employment relations in mediatized workplaces in which the boundaries of professional and private life are becoming more fluid. -- Design/methodology/approach -- A qualitative approach was employed to explore this relatively new phenomenon. The data, comprising 24 interviews with managers responsible for corporate communication and human resources in knowledge-intensive organizations, was thematically analysed. -- Findings -- The analysis shows that employees' work-related social media use creates new types of exchanges and dependencies between an organization and individual employees, which relate to employees' representation, knowledge and networks. -- Originality/value -- The study is among the first to examine the exchanges and dependencies in an employment relationship that emerge from increased use of social media for professional purposes.