E-mail-based conversations between thousands of people-very large-scale conversations (VLSCs)-now take place in a variety of on-line public spaces such as Usenet newsgroups and large listservs. This article describes the author's prototype Conversation Map system, which can automatically analyze and graphically summarize thousands of e-mail messages exchanged in VLSCs. Example conversation maps of nine VLSCs are presented. Finally, the sociolinguistic analysis performed by the Conversation Map is discussed as a form of artificial dialectics, and the graphical summaries produced by the system are considered as potential common ground between participants in a VLSC.
"Free speech" can mean not only face-to-face communication, but also expression embodied in the media of newspapers, books, television, film and so forth. Many of these media constitute public "spaces." With the introduction of each new public space, the theories and practices of "speech" and "conversation" are affected and extended. This article concerns a philosophical study of and artistic-design approach to some of the new, electronic, public spaces of the Internet and the forms of "speech," "conversation" and dialectics practiced in these new spaces.
The new electronic spaces that I am interested in have the following characteristics in common:
• They are large. Many server sites now support interchanges between hundreds and thousands of people. Usenet newsgroups and large listservs are the most common of such sites. I call these usually text-based, usually asynchronous interchanges very large-scale conversations (VLSCs) .
• They are network based. More specifically, they support network-based communities. The boundaries of these spaces and of the communities they support are not geographic boundaries. Communities of artists, writers and scientists are examples of pre-Internet, network-based communities, i.e. communities based upon a social network and some shared interests or needs. Network-based communities are different from geographically based communities like neighborhoods, cities and nations. Network-based communities-e.g. the scientific community-have continued to grow with the help of new network technologies, but contemporary technologies have also engendered a variety of new communities, e.g. the open source community.
• They are public. As more and more people gain access to the Internet from their homes, libraries or schools-rather than from their workplaces-the Internet increasingly becomes a space for public discussion and exchange. Very large-scale conversations are a common event within the confines of large industry-e.g. the huge number of communications between thousands of people necessary to design and build an airplane or coordinate the production of a film. However, these have a distinctly different character than the VLSCs in which people are participating as individuals rather than as employees. The Internet is engendering the production of new public spaces that may offer the means to reinvigorate public discourse [2-4].
From the perspective of the history of media, the VLSC is a new and mostly unexplored phenomenon. At no other point in history have we had a medium that supports many-to-many communications between hundreds or thousands of people. A VLSC takes place across international borders, often on a daily or hourly basis. Unlike in older media (e.g. telephones) participants in these VLSCs usually do not know the addresses of the others before the start of a conversation.
The social-scientific theories and tools we currently have for understanding and investigating conversations and discourse include those of discourse analysis  and conversation analysis . These existing theories and techniques can handle the analysis of small-scale conversations, e.g. interactions between 30 or fewer people. But it is not obvious how the existing methods can be scaled up to handle the huge, many-to-many interactions that have now become commonplace on the Internet. So the challenge is this: What software can be designed to help us navigate the new public spaces of VLSCs?
Michel Foucault pointed out that "the comparison between medicine and navigation is a very traditional one" . Medicine, navigation and government have to do with self-guidance, control and governance. Etymologically, the verb "navigate...