Exploring an online conversation can be very difficult for a user, especially when it becomes a long complex thread. We follow a human-centered design approach to tightly integrate text mining methods with interactive visualization techniques to support the users in fulfilling their information needs. The resulting visual text analytic system provides multifaceted exploration of asynchronous conversations. We discuss a number of open challenges and possible directions for further improvement including the integration of interactive human feedback in the text mining loop, applying more advanced text analysis methods with visualization techniques, and evaluating the system with real users.