A system and method for the late-binding of time-based media in real-time. With late binding, the sender may create time-based media before or at the same time an active delivery route to the recipient is discovered. As soon as the route becomes available, the media is transmitted. The existing DNS and email infrastructure is possibly used for route discovery, while any real-time transmission protocol may be used for the actual delivery of the media. “Progressive” emails may also be used for the real-time delivery of time-based media.