: One virtue of instant messaging is informality. As messaging is used more in work settings, being able to consult an exchange later can be beneficial. However, archived communication often becomes more formal. We describe a case study of IM use that illustrates such a transition. In this and some other respects, messaging seems to be paralleling the history of email use. This points to an ongoing tension between our need for informal interaction, even in workplaces, and the ease and occasional benefits of archiving digital information.