A communication application configured to support a conversation among participants over a communication network. The communication application is configured to (i) support one or more media types within the context of the conversation, (ii) interleave the one or more media types in a time-indexed order within the context of the conversation, (iii) enable the participants to render the conversation including the interleaved one or more media types in either a real-time rendering mode or time-shifted rendering mode, and (iv) seamlessly transition the conversation between the two modes so that the conversation may take place substantially live when in the real-time rendering mode or asynchronously when in the time-shifted rendering mode.