The World Wide Web is a global hypermedia system which makes locally created and stored documents available for recipients at geographically non-local sites all over the world. Hypermedia documents distributed in this way do not generally contain solely textual information. Other semiotic elements: icons, images, graphics, animation, sound and video sequences are often embedded in these documents, hence the common use of the term `hypermedia'[3] used above to denote both the general type of global distribution system, as well as the particular type of documents which the system distributes.
Hypermedia documents may contain indexical links which allow readers to `jump' more or less instantaneously to similar documents with related information stored at other sites. Distributed hypermedia documents from non-local sites may be retrieved, stored and printed out locally. They may also provide access to distributed software resources (generally known as applets) which reside at non-local sites and which are linked to their parent documents through scripts so that they can be `called up' and run locally whenever the functions they are designed to provide are needed. In addition to being navigatable (by following links) and readable, hypermedia documents also allow other forms of direct interactions on the part of readers, such as filling out forms or questionnaires for the non-local collection of information, and activation of search engines to retrieve information from non-local databases.
The World Wide Web may be seen as an non-contemporaneous form of distributed virtual environment, providing access to huge numbers of interlinked, cross-indexed, multi-levelled hypermedia documents, each of which may be considered as representing a tiny sub-environment in a vast global virtual library. Visitors to the library `enter', read and explore the environment by navigating within and between sub-environmental `nodes' through `gateways' created by locally run software resources (Web browsers). In principle any individual, group or organization with access to the Internet who wishes to establish a World Wide Web entry point or `node' - a `Web Site' - of their own, can do so by setting up a computer server to store and make accessible hypermedia documents and other digital resources, and by creating and inviting the establishment of links to and from these documents to resources at other sites.
Since we are primarily concerned here with `conversational' aspects of this technology, we shall go on to consider some types of exchange carried out by means of the World Wide Web which might be subsumed under the more general notion of `conversations'.
Face-to-face conversations are first and foremost contemporaneous events - they happen in real-time. They are also sequentially organized - one form of communicative action (an initiative or response) follows upon another, generally in rapid sequence. There is a degree of cohesion between grammatical elements actualizing communicative actions, and a coherent form of semantic structure is developed in the course of the conversation and this is reflected in the weaving together of elements of meaning which actualize global, thematic and local coherence levels[4].
As we have seen previously with the case of e-mail, any extended, cohesive, semantically coherent initiative-response sequence occurring over time may in a very general sense be considered `conversational'. This includes also those sequences which are developed non-contemporaneously. This means that non-contemporaneous exchanges initiated by means of hypermedia documents which invite to interaction with their creator(s), either through electronic mail or the insertion of data into interactive forms, crossing off of choices on a list etc. may also be labelled as `conversational' in this wider sense of the term. However, since interlocutors are neither physically nor temporally co-present while taking part in non-contemporaneous conversational activities of this kind, important phenomenal factors in face-to-face communication which cannot necessarily be compensated for by other forms of expression such as writing, still or video-images, graphics or animations are lacking. These include direct perceptions of interlocutor appearance, global body language, gaze, facial expression, eye-contact, proximal relations of self to other and environment, movement, tactile impressions, body warmth, body and breath odour.
Similar considerations with regard to a general kind of `conversationality' may also be applied to certain other types of human-machine interactions. Into this category fall activities like using natural language processing systems to search distributed databases, navigating the World Wide Web through hypertext links evoking language-based choice trees, and managing file hierarchies on local or non-local computers using operating systems which invoke dialog boxes at choice nodes in the file management process. Conversation-like human-machine interactions of this kind display certain similarities to face-to-face conversation, in that the outcome of certain types of intitiative will often lead to some kind of conventional response. This is after all what we generally will experience in about eighty percent of all our everyday conversations.
On the other hand, however, human-machine interactions lack a shared sense of physical co-presence on the part of interlocutors (after all, one is embodied and the other not). They also lack a shared sense of intersubjectivity associated with the experience of verbal and non-verbal realizations of one another's emotional reactions to what is being said, and of one another's inferencing and interpretation processes. Mainly due to these last two factors, certain types of face-to-face conversation are characterised by a very high degree of spontaneity, creativity, open-endedness and non-linearity which makes them rather unique as forms of conversational activity, in this wider sense of the term.