FACULTY AND RESEARCH

Enterprise Social Media (ESM) has gained significant momentum in the workplace and has been presented by both practitioners and academics as the new alternative workplace communications technology to substitute email. However, our knowledge is limited when it comes to explaining how ESM integrates the media portfolio and the extent to which it can or cannot replace email use. Adopting a grounded methodology, we conducted a case study in a large multinational corporation specialized in the beauty and well-being sector, in which we found that ESM superimposes the existing media and thus creates a millefeuille effect. Grounded in our case study, we explain the millefeuille effect in the specific case of ESM over email and develop a revised version of the millefeuille theory. Our findings show that the millefeuille effect emerges from negotiation between the perceived affordances enabled by ESM and its imposed constraints, and from that of email with regard to communication norms and routines and the context of IT use. The results highlight the need for managerial engagement in ESM that goes beyond its sponsorship alone. Our study revisits the millefeuille theory by adopting three theoretical lenses to explain the millefeuille effect: a media portfolio features lens, a norm and communication routine lens, and a context-of-IT-use lens. We contribute to the IS literature by proposing a revised version of the millefeuille theory that integrates the affordance lens. By taking into account the features of the media portfolio and how they are appropriated by users, we gain a clearer understanding of the millefeuille effect. We also come up with some recommendations to help managers deal with media overload and cope with the associated risks related to the millefeuille effect.