Social media is used by the majority of Swedish municipalities. However, the highly interactive features of social media are often not taken advantage of. The study aims to get a better understanding of why social media is not used to its full potential in the municipality. Findings from an interview study with communicators in three Swedish municipalities reveal that the motivation for using social media is often difficult to turn into action. Tensions emerging in the use of social media result in hesitation, uncertainty and a slowing down of work practice. The processes of managing the tensions are characterized by boundary crossing between different communities, such as municipal communicators, elected officials and citizens, with social media itself as an equally important actor. The processes of boundary crossing by the municipal communicators are discussed in terms of learning processes and new emerging competences that might redefine the role of the municipal communicator and hence perhaps the public servant in general.