Communication is the transfer of information between a speaker (sender, writer) and a listener (receiver, reader). Communication is asynchronous when the speaker and the listener perform the communication at different times. Distance communication allows the speaker and the listener to be in different places. At present the ultimate form of asynchronous, distance communication is the book, requiring the reader to be neither in the same time or place as the writer. Media that support both Asynchronous and Distance communication will be referred to as ADC media.
Traditional forms of communication between humans include written communication, including text, images, and drawings, and voice-centered communication, spanning the range from full personal interaction through voice mail. Common modes of communication include:
Traditional ADC media, including print, telephone, and broadcast, each support different combinations of these forms, modes, and degrees of cost and convenience for asynchronous or distance access.
Focus on digital networks is the consequence of widespread interest on the Internet (a medium for distance communication) and the world-wide web (WWW - an ADC medium). While text and voice have been well-supported by print, telephone, and more recently e-mail, part of the interest in the WWW is its low-cost support for non-traditional forms of communication such as hypertext (text with links), images, animation, and store-and-forward sound and video. What the WWW is less well-suited for is interaction, a mode of communication supported on the Internet by chat rooms, ``talk'', the MBone [5], and Internet and video telephony [7].
In this abstract we explore more advanced applications of digital networks which are currently starting to become practical due both to improving cost and bandwidth on digital networks, and to newly developed and implemented standards. These applications include interactive video-conferencing and shared whiteboard and workspace interaction, together with store-and-replay for asynchronous access and multimedia e-mail for asynchronous interaction.