After massive and rapid consumer adoption in recent years, Instant Messaging (IM) applications are beginning to move into the workplace. We investigated the adoption of IM from four months before to three months after it was formally introduced in a mid-sized organization involved in knowledge work. Employees were free, within reasonable limits for private use, to use IM or not, not only with internal contacts (colleagues) but also with external contacts (work relations, friends, family). Based on data obtained before and after introduction from surveys, interviews, and communication traffic logs, we investigated the adoption of IM by individual users and pairs of users.

We found a sudden and stable fourfold increase in IM use after introduction, both in terms of users and the number of conversations. IM users primarily report that IM improves the way they reach others and can be reached themselves. Technology self-efficacy, perceived compatibility of IM with work and pressure from social contacts at work to use IM explained best why some employees adopted and used IM more than others.