Emerging web-based communication technologies have made it possible to build rich, modular interpersonal communication suites. Leveraging these new standards, we designed an experimental service named "Le Fil", which provides users with longlived conversations where they can engage in a variety of activities, in a synchronous or asynchronous way. Built around some strong assumptions about what rich communications services must offer, our prototype, and the lessons learned from actual user tests conducted during the design process, shed some light on benefits and current issues raised by such a data-centric approach to interpersonal communication.