Instant Messaging (IM) is a useful tool for collaborative work. However, the awareness and communication features of IM pose a tension with privacy desires. Inadequate support for managing privacy could lead to suboptimal use of IM and thereby undermine its benefits. We conducted interviews and an Internet survey to understand privacy attitudes and practices in IM usage. Based on the findings from these studies, we designed an IM plugin to improve the support for privacy management in current IM systems. The plugin detects conflicts in privacy preferences, notifies the parties involved, and allows negotiation of a resolution. It also encrypts the communication channels and archives, allows different privacy preferences for different contact groups, and provides visualizations to facilitate the comparison of one’s own IM activities with those of any IM contact group. A usability evaluation of the plugin indicated that it succeeds in its goal of providing IM users with better pr...