E-mail is one of the most successful computer applications ever developed. Despite its success, it is now dogged by numerous problems. Users complain about feeling overwhelmed by the volume of messages they receive, they have difficulties too in organizing and managing their e-mail data but, most importantly, they have problems in using e-mail to manage collaborative tasks. These require extended interaction with others for their definition and execution. As a result, users are often concurrently working on multiple outstanding tasks as they await responses from others concerning these tasks. This requires users to (a) create reminders, (b) identify messages that relate to the same task, and (c) combine information from these related messages.
Currently, people try to use the email inbox to do this but our data indicate it is ineffective for these purposes. Other recent approaches attempt to tackle Collaborative Task Management but we show that these offer at best only partial solutions. In contrast, we present two systems, TeleNotes and ContactMap, that directly address Collaborative Task Management. These are motivated by empirical research into paper-based and people-based task management strategies. We describe how our systems implement these different strategies and present evaluation data for each system in use. We contrast the success of these two approaches with earlier work and discuss outstanding design and theory problems arising from our research.