This paper presents a longitudinal case study of the introduction of voice mail, applying media richness theory to develop and assess a set of 16 tasks with varying levels of equivocality, and to compare different media. Through t-tests, reliability, factor, and multidimensional scaling analyses, evaluation of task equivocality and voice mail is discussed and potential shortcomings of current approaches are highlighted. Results show that equivocality does not seem to be unidimensional and includes aspects of authority across organizational boundaries. Across all tasks, telephone would be most likely selected by respondents, but face-to-face and telephone were more likely to be selected for more equivocal tasks. Unlike prior studies, voice mail is perceived as similar to documents and face-to-face.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>