This paper investigates the impact of social media-use on communication processes within organisations. Findings from three qualitative comparative case studies are analysed through the lens of the resource based view of organisations. The analysis follows comparative logic focusing on similarities and differences in case-settings and outcomes. Each of the cases represents an organisation with workforces of similar size, composition and distribution but with qualitatively different approaches to social media-use and, as expected, different effects of social media on processes and capabilities. The findings suggest, that the value of social media in contrast to other IT technologies is derived from its use for relationship-building (who the users are connected to and how) rather than information storage and dissemination (what do the users know and where they find it).