The paper presents a critical inquiry into the relationship between Computer-Mediated Communication (CMC) and progressive rationalisation in modern organisations. By drawing on the evidence from a field study of a University consultative process, the paper investigates how communicative practices embedded in a public discourse via CMC influence rationalisation of organisational processes. This investigation has been conducted within a theoretical framework of social interaction derived from a particular interpretation of Habermas’s theory of communicative action in an organisational context. By interpreting electronic messages as linguistic acts and social actions, the paper seeks to provide a new insight into an appropriation and use of CMC. Moreover, by analyzing communicative practices in the light of relationships between social actions, systems rationalisation and lifeworld rationalisation, the paper seeks to explain both visible and hidden impacts of the public discourse via CMC on the organisation.