Overview of Fifty-Two Media

For the purpose of creating a set of cases that might be used in exploring a typology of communication media, fifty-two different forms of communication have been identified. This list should not be expected to represent a comprehensive review of currently available media. Still, it covers most of the major communication media in current use. The media identified span both interpersonal and mass communication, as well as the "grey area" that lies between.

This appendix will review those media and their essential characteristics. The reviews will not attempt to describe these media completely in terms of the characteristics outlined in the previous section except where those characteristics are essential to a description of the media.

Traditional Media

Of the fifty-two, fourteen might be thought of as traditional media. All either predate the technological innovations of the late nineteenth century or directly derive from media that does. This should not be taken to mean that these media have not changed, or even improved over the last 100 years as the result of technological innovation. Several have changed and even improved substantially as a consequence of the use of advanced technology, including computer technology. By the same token, however, several of these media have not changed in any significant way over the last hundred (or even thousand) years. These traditional media include the following:

Face-to-Face (Dyadic)

Communication between at least two, and at most a few, people who are physically propinquitous. Its the kind of communication that most people engage in most commonly (e.g. talking to our friends, families, neighbors, and business associates one on one). Face to Face communication has the highest physical bandwidth of any form of communication, with all of the five channels (including both verbal and nonverbal channels) available.

The medium is fast, with speeds and interactivity in the immediate range, but has no inherent persistence. Face-to-face communication most commonly occurs at short range, with participants in a conversation separated by inches or, at most, feet. Although conversation is often a spontaneous act in which communication occurs because people are together, the target is presumed to have traveled to the location of the message in this medium.

Face-to-face communication is the central focus in the study of Interpersonal Communication, in which the range of communication is sometimes described as "face-to-face communication, and its variants".

Small Group

Communication between at least a few, or at most a few dozen, people who who are physically propinquitous. Small group communication is a clear derivative of face-to-face communication in which the biggest differences are bandwidth (smell/taste exits the picture as effective channel), and distance (distance must be measured in feet and sometimes tens of feet). These differences have important implications, however, and the small group communication process can be complicated by a range of factors that rarely enter the face-to-face communication process, including cliques, leadership and the problems of reaching a consensus or even finding common ground. It is generally studied as a specialty of interpersonal communication.

Public Speaking

Public Speaking is communication from one or a few people that is directed at a larger physically propinquitous group. The audience may range from tens to hundreds of thousands, although audiences measured in the tens are probably most typical. Like small group communication, public speaking is a clear derivative of face-to-face communication. Besides the already stated differences in audience size, bandwidth is further reduced (touch exits the picture as effective channel), and distances increase (distance must be measured in tens of feet and sometimes hundreds of feet).

The differences are important, however, and although immediate feedback remains available, the nature of that feedback, and the way messages are presented, changes. Public speaking is generally studied as Rhetoric, an entirely separate specialty from Interpersonal Communication. Indeed, although Interpersonal Communication and Rhetoric often fall within the same department at many schools, they are increasingly regarded as distinct disciplines. The distinctions may not be entirely justified, but scholars in these areas increasingly find themselves separated by both subject matter and methodology.

Notes, Memos, and Letters

These three media, all of which are generally either handwritten or typed, are all fairly similar in their essentials. All are personal written documents that are most typically written by one person and sent to another. For all, the message most typically travels to the target and the bandwidth is most typically restricted to a single (written) channel. The use of each can be usefully distinguished, however.

One might leave a note on someone's desk or pass one under the table. One would rarely do the same, however, with a memo or letter, which are generally regarded as more formal documents. A note can be regarded as "a short informal letter", as it is defined in Webster's, but that description probably overstates what a note is. We will regard a note as a short document, usually no more than a few sentences long, that is most generally passed directly from the source to the target. These characteristics make notes fairly quick and highly interactive.

Letters, on the other hand, are generally longer, and often somewhat formal, documents. Letters will typically be transmitted long distances by mail in an envelope, and will almost never be hand-delivered to the target by the source. These characteristics make letters a much slower and less interactive communication medium than notes.

Memos fall someplace in between, and are generally regarded as a mode of informal business communication. Memos are frequently used to document conversations or to serve as a reminder of coming events. Like letters, memos will typically be transmitted from source to destination by a third party. Since the transmission will typically span a shorter distance (many memos never leave the building they are written in), however, the third party is more likely to be a mail room than the post office, and the transmission time and interaction time will generally be shorter than letters, but longer than notes.

Notes, memos, and letters properly belong to the study of interpersonal communication, but have generally been neglected as a locus of study. Memos have seen fleeting attention from scholars of organizational communication (a specialty within the study of interpersonal communication. Letters are most often the subject of case studies by scholars of language, literature, history, and psychology, but it is generally the writer of the letters that is targeted for study rather than the letters themselves.

Newspapers, Newsletters, and Magazines

These mass media are the core of the study of journalism and, to a lesser extent, of mass communication. They are predominantly one-way human communication systems in which messages are broadcast to large numbers of people. Like letters, these are written or printed media, and in order to reach large numbers of people, they must be reproduced in equally large quantities. This entails a cost in the speed of delivery, however, as the preparation, reproduction, and transportation of print media. It can involve substantial amounts of time.

The most remarkable of these media, in many ways, is the daily newspaper, an often substantial document which manages to repeat this process every 24 hours. It is not unusual for a daily newspaper to include hundreds of pages and yet reach hundreds of thousands of people each day. Even within these limits, a daily newspaper can be remarkably responsive, and under the right conditions, it can bring details of news to its readers within a matter of hours.

The weekly newspaper, by contrast, is a very different document. Where the scale and economics a daily newspaper will generally require that it serve a region and obtain a circulation that at least approaches the hundred thousand range, the weekly newspaper can get by on much smaller numbers. There is little pressure to keep up with late breaking events, and a much smaller staff can be focused on covering the local events of a town or industry.

The scale of newsletters is even smaller than the typical local newspaper, both in terms of circulation and physical size. A typical newsletter appears once a month and is anywhere from eight to 25 pages long. Many commercially successful newsletters have circulations that measure in the hundreds or thousands. Commercial success is not the object of most newsletters, and it is currently possible to cover the publication costs of a newsletter on subscriptions of as little as $10.00 a year. Successful commercial newsletters, however, will often charge hundreds of dollars for a yearly subscription. Lead times for newsletters is generally fairly long -- in the range of weeks. The small size of the newsletter often makes it flexible enough to allow coverage of late breaking stories, however, and newsletters are often the fastest traditional means of breaking news within narrow areas of interest.

Magazines, which most typically appear on a monthly basis, are typically the slowest of these media. Lead times for magazine articles are often measured in months. The magazine makes up for this handicap with high production values. Color pictures, better quality paper, in-depth writing and other features allow the magazine to attract a large audience. Most of today's magazines can be thought of as slick, high volume newsletters that target a narrow area that interests a mass audience.

Journals

Among periodical literature, the journal is the best example of a specialty publication. Journals are, with very few exceptions, scholarly publications with narrow specialties, small circulations that rarely exceed thousands, and extremely long lead times which are often measured in years.

Books

A book is a one shot communication media in which one person generally attempts to deliver an extended message to a lot of people. Lead times for book publication are usually fairly long, and are typically measured in months. When pressed, however, a publisher with a "hot" property can bring a book to market within a week.

Art

One doesn't usually think of Art -- paintings, statues, photographs and other art forms -- as a human communications media, but insofar as it is a means for delivering a message (however cryptic) to an audience, it is. Most art uses a single channel (sight) to communicate its message, but some three dimensional forms which we will loosely clump under the name dioramas, involve two channels (sight and touch).

Technologically Mediated Systems

Another twenty-four media, almost all of which have emerged within the last one hundred years, can be labeled as technologically mediated communications systems. These media include:

Telegrams, Telex, and Facsimile

Each of these media is a high speed hard copy substitute for written correspondence. Of the three, the telegram is the oldest medium, dating back to the mid-nineteenth century, and the slowest, with final delivery to the target made by a person. Telex and facsimile are distinguished from telegrams by their relatively direct delivery systems. Messages originate from, and are delivered to, equipment that is generally located directly at the business location of the source and target.

Telex concentrates on messages, and is distinguished from telegrams only by its relatively direct delivery system. Facsimile concentrates on image data (including text images). Today these media are increasing computer-mediated, and telex is becoming indistinguishable from electronic mail in some ways, but telex operated successfully well before the first practical computer was built, and facsimile has only recently moved from analog to digital technology.

Tape Letters, Recordings, and Video Recordings

Sound recording dates back to Edison's invention of the phonograph in the late nineteenth century, and although the technology has changed and diversified tremendously in the time since, the basic applications have changed very little. After all of the varied tape and record formats that are currently available are taken into account, three (and arguably four) forms of communication stand out. Recordings and Video Recordings, whether distributed by record or tape, are basically one way mass media. What we will call tape letters, the recording and mailing of a spoken letter, is essentially an interpersonal media.

Filmstrips, Beeping Filmstrip, and Multi-Media

Each of these media, which can be presented as foils, slides, or a continuous "filmstrip" are fundamentally built of still pictures that are sequences toward some effect. Of the three, the filmstrip is the simplest -- nothing more than a slide presentation. The "beeping filmstrip" is more complex, as it is coordinated with an oral script which is sometimes, but not always, prerecorded. The multi-media presentation is the most complex, and will often involve the coordination of several distinct series of images, with each series projected simultaneously. All are one-way presentational media.

Silent Film, Film, and Film with Subtitles

Another Edison invention, film, allows us to record and play back moving images. Each of the three forms noted here is distinguished by the number of channels involved. Silent film is essentially a non-verbal media, and although many silent films are sprinkled with dialogue subtitles, they are generally secondary to the action. Film (or talking pictures) coordinates recorded sound to the action, and effectively killed silent film as anything but a recreational medium the day it first succeeded. Film with subtitles is an adaptation of the film media for audiences that do not understand the language spoken in a film, and written communication is central to the presentation.

Automatons and Talking Automatons

Walt Disney didn't invent the idea of three dimensional figures that moved and acted like people or animals, but he and his associates certainly perfected the technique. Some of the many many such figures that can be found at Disneyland and other Disney Attractions talk as well as move. Many simply move. But they unquestionably communicate in either case.

Radio and Television

These broadcast media have become the dominant mass media of our age, and it can be argued that Americans spend more time engaged in this kind of communication than in any other, including face-to-face communication. Radio is a voice only media, and can be usefully differentiated from talk radio, which, because of its creative use of the telephone as a medium of limited audience interaction, is somewhat interactive. Television, like film, combines voice and image, but unlike film, delivers its message directly to the target or targets address.

Intercom, C.B., Ham Radio, Telephone and TeleConference

These five media are all voice only interactive media that provide a long distance analog to face-to-face communication and, in the case of teleconferencing, small group communication. The fundamental characteristics of these media are fairly similar. All involve a single verbal communication channel that permits rapid communication between two or more people.

VideoPhone and VideoConference

The videophone is a failed two channel (voice and image) alternative to the telephone that will probably reemerge as a successful communication medium at some point in the future. The VideoConference is a somewhat more successful variant on the VideoPhone that allows small groups in diverse locations to hold a joint meeting.

Computer Mediated Systems

Finally, it is possible to identify at least fifteen computer-based human communications media that are either already in service or fairly close to reality. This list is anything but complete, and other forms of computer-mediated communication will be mentioned in passing even though they are not considered explicitly. Note also that the differences between some of these media are sometimes defined by the nature of the equipment used and the capabilities offered.

Here is our group of computer-based media:

Electronic Quips

Very short person-to-person messages, usually no more than one line (sixty to seventy characters; ten words) long that are broadcast directly to the terminal of the target or targets. These messages can be somewhat hit or miss. In general, if the target is looking when this message appears, it will be seen. If not, it won't be seen. Such messages generally have no inherent persistence, and may be difficult for the target to preserve in any case.

Electronic quips were probably the first form of computer mediated human communication, and are often used by computer operators to warn users of impending problems and shutdowns. When electronic quips are used in this way to broadcast messages to large numbers of users, the quip can serve as a mass media event. The speed and flexibility of electronic quips make them highly interactive, however, and it is possible to have a very good conversation by "quipping".

Indeed, CompuServe's C.B. simulation raises quipping to a true conversational medium, in which a number of conversations, each of them a series of one line messages, occur simultaneously on the same channel. A participant in any of those conversations can monitor all, and some participants jump from conversation to conversation. In truth, the party line aspects of CompuServe C.B. make it a distinct medium from both electronic quips and from computer conferencing, which it also bears similarity to. "Electronic party lines" will not be treated here, however.

Note that, although electronic quips are fundamentally one-line communication events, larger messages can, and frequently are, constructed by spreading a message across several quips. Note also that quips are asynchronous on a line-by-line basis, and that people who are interacting can prepare quips simultaneously and independently. These characteristics can lead to interesting effects, particularly when quips are interactive, as a reply may be received in the middle of a message, and because one participant may shift the focus of the conversation before the other has finished the previous thread. Hence the content of messages in "quip conversations" will often be somewhat "out of synch", and will regain synchronization only through the coordinated efforts of both participants.

Watching these synchronization problems can reveal a great deal about the problems of synchronization in face-to-face interaction, where messages cannot be delivered asynchronously. People are individual information processors that bring their own interests and motivations to a conversation in which only one person can deliver messages at any time, and the message delivered at any given point in time exercises some control over what messages will be appropriate at subsequent points in time. As a result, they often prepare messages that are never delivered because the focus of conversation changes before a proper opening arrives.

Indeed, it can be argued that face-to-face and small group interaction are subject to a kind of brownian motion, in which the specific focus at any instant is largely a function of the local effects of the most recent messages. Because electronic quips can be prepared asynchronously, however, messages that might not be delivered in a face-to-face conversation are very likely to be delivered in a "quip conversation". This changes the dynamics of the conversation considerably, increasing the likelihood that are participants will be able to express their interests and concerns, and making it possible to trace the shifting tides of interaction more closely.

Electronic Mail

The computer mediated equivalent of letters or memos, with very similar characteristics to letters in every area except speed and interactivity. If the target is available when electronic mail arrives, the speed with which it travels from source to destination may be measurable in seconds, even when the source and destination are separated by thousands of miles. This speed makes electronic mail considerably more interactive than the traditional letter is, with the level of interaction limited less by the characteristics of the media than by the habits of the interactants.

Voice Mail

A voice-only equivalent to electronic mail in which the source can record a message which is delivered to the target at either a predetermined point in time or at the convenience of the target. Some of the characteristics of voice mail can be captured with a telephone answering machine, but true voice mail requires the mediation of a computer.

Electronic Bulletin Board

A computer based equivalent of the bulletin board; a place where messages of general interest can be posted and read at the convenience of the end user. Most timesharing systems include some sort of bulletin board that is displayed every time the user starts up a session. Bulletin boards that can be accessed at the option of the user are frequently available as well.

These bulletin boards can be thought of as the functional equivalent of a daily newspaper, and although they can often be updated more frequently than that, daily updates are a common characteristic of electronic bulletin boards. They have more in common with bulletin boards, however. Items will commonly appear and disappear asynchronously, with most items maintained for a predetermined, and generally limited, period of time.

On-line Information

One would not typically think of a database as a human communication media. A collection of information can be used as a basis for the content of communication, and even as actual content, but one would rarely regard it as an actual means of communication. A database might become a book, or a regularly published section in a newspaper, or even a regularly published periodical, but the best that one could have said for it is that it was a genre. Medium would have been far too strong a word.

A computer-based database is now more than simply a collection of information, however. It is a way of communicating information that is distinctive, whether one compares its characteristics to previous generations of database, or to other communications media. Today, electronic databases can be updated constantly as new information, or corrections to old information, becomes available. Those with a strong interest in the contents of a database can often monitor changes in important data so that they know about changes as soon as they happen. This makes the on-line database an almost interactive mass media.

On-line information can also be readily and automatically searched (independent of indexes) for key words, making it possible to find specific existing information very quickly. This search capability has changed the nature of what a database can contain as well, and on-line databases are increasingly devoted to maintaining information that would never have existed in a database (or even have been saved) without the computer.

Electronic Publishing

Given the other media that are made possible by computer mediation, it should hardly be surprising that the functional equivalent of articles, books, magazines, newsletters and even newspapers could be published on-line. In fact, publishing a document on-line is becoming a trivially simple event, especially given the convenience of creating and editing documents on computers.

What may be surprising, however, is the erosion of boundaries that occur when traditional mass media are transferred to a computer. The publishing frequency and style of print that differentiate traditional print media are the result of economic forces, including the cost of subscriptions and the size of the subscriber base, and the resulting product is clearly recognizable, not only by how often it is published, but by the quality of the paper used, the way it is bound, and how it looks. The forces that shape the differences between newspapers, newsletters, magazines, journals, books, and other traditional mass media are completely different in the computer-mediated world. Consider the following:

These factors should make it difficult to tell the difference between an electronic newsletter, an electronic newspaper, an electronic magazine, an electronic journal, or an electronic book. When the editor of a newsletter moves that document on-line, there is little incentive to publish the newsletter in the same manner it is published in hardcopy. Quite the contrary, the economics of the electronic newsletter encourage the placement of new articles on-line as soon as they are available, as that encourages subscribers to check out the newsletter more often.

The same is true of newspapers, magazines, journals and even books. All can be updated whenever new information is available. Hence books can become living documents in which an audience can share an author's changing vision; journals can become fairly timely documents in which new research can be published as soon as the reviewers clear it; and magazines, newsletters, and newspapers become indistinguishable by any criteria except size and scope.

The physical characteristics of electronic publication, although irrelevant to the factors which have redefined these media, only serve to accentuate this sameness. There are no differences in paper quality or the way documents are bound on-line.

There will be a range of different electronic print media, but the differences will not mirror the differences inherent to traditional print media. The factors that are likely to differentiate electronic print media include:

Interactivity
Computer-mediation allows mass media to be much more interactive than has been the case in the past. It is not unreasonable to expect that, at some point in the future, a reporter who files an article about a news event will then enlarge and polish that article on the basis of feedback from readers.
Machine Intelligence
Because computers can be programmed, it is possible to build a certain amount of interactivity directly into a program. This makes it possible to write books that actually change in response to the reader. The result, interactive novels that lie somewhere between a game or simulation and our traditional notions of a book are already a reality and, more importantly, a huge commercial success.
Flexible Structures
It is possible to write books and other documents on computers in formats that would be impossible to publish in the real world. One such format is a tree structured document in which documents can be footnoted with documents that hide beneath the surface, available on request. This nonlinear document form allows documents to be written with depth so that a person can read it at whatever level of detail seems appropriate.

If this paper were written in this form, the entire document might be encompassed in what is currently its first sentence: "The use of computers is changing the way people communicate, and the changes are just beginning." The abstract could hide behind that assertion, with various chapters hiding behind phrases in the abstract, and chapter elements hiding behind phrases in the chapter. A document written in this way would be akin to a field of rabbit holes through which whole new worlds of words and detail can be found.

Compound Documents

One of the key limitations of current computer-mediated print media is that they are, by and large, limited to the use of text and text graphics. The technology for mediating voice and graphic communications already exists, however, and it is simply a matter of time before it becomes practical for computer media to handle messages that use these channels in conjunction with text. Compound document forms should include:

Voice over data
In this media, the source of a message can annotate documents verbally, providing an easy method for emphasizing key ideas.
Mixed text and graphics
High quality hard copy documents mix text and graphics on the same page. Computer media are increasingly capable of handling documents that are formatted in this manner.
Voice over mixed text and graphics
By extension, it should also be possible to voice annotate documents composed of mixed text and graphics in the near future.

Asynchronous Computer Conversation

Most of the computer media that have been introduced are characterized by a high degree of Interactiveness and at least one, electronic quips, can even be used conversationally. Because the computer quip only allows the transmission of a line at a time, however, it does not allow true conversation. What it does allow is a long distance equivalent to passing notes under the table.

True computer conversation requires that the composition and transmission of messages be instantaneous and simultaneous -- that you be capable of reading what I write as I write it. Meeting these conditions is not difficult, however. Indeed, one form of computer conversation, asynchronous computer conversation, is almost trivially easy to implement and is a daily event for large numbers of people who establish direct communications between personal computers.

In this medium, conversation is "character asynchronous". Each character typed by either person is immediately transmitted to the other computer and displayed. Character asynchrony is probably an undesirable characteristic from the standpoint of maintaining an orderly conversation, but it is a wonderful medium for watching how people interact. When two people "talk" at the same time, characters overlap on the same line, sometimes making it impossible to tell what either person has said. Clearly, the interactants must synchronize their behavior so that only one person "talks" at a time, just as they must in a face-to-face or telephone conversation. Computer mediated "floor fights" directly correspond to real behavior in face-to-face interaction, as well, but with some important differences.

First, all communication is written, and many of the cues that we used to maintain synchrony in face-to-face or telephone conversations are not available. There are other cues, of course, but they are not conclusive, even for an experienced speaker. Hence, character asynchronous computer conversation could provide the basis of some interesting studies of how people fight for, maintain, and trade the floor during conversations.

Computer Synchronized Conversation

The fact that asynchronous computer conversation mirrors reality does not make it desirable, however. It is frustrating watching your words disappear in a puddle of floor fight gibberish, just as it is frustrating to sit on an idea in a conversation because someone else has won the floor. Ideally, one would like the computer to mediate who says what when in such a way as to:

In other words, one would like to build a medium that allows two people to talk at once and still hear what the other person is saying. Electronic quips clearly show that this can be done, at least for lines of text. The challenge is to do the same for sentences and paragraphs and still transmit each character as it is typed.

This challenge can be met in a variety of ways. The simplest and least satisfactory solution is to split the screen so that the messages of each interactant appear in their own "window". This solves the first problem. Two people can talk at the same time. It is not ideal, however, because the conversation cannot easily be integrated into a single integrated transcript.

A better solution assumes that a computer can be taught to recognize the boundaries between paragraphs and integrate the messages of several people within a single display window. This machine induced synchrony allows people to build messages when they want to, even when another person is talking. This should have several effects which will generally be considered to be positive:

These advantages will be particularly apparent when voice recognition systems are perfected to the point where voice can be converted into data in real time with a high degree of accuracy. This kind of simultaneous interaction, when coupled with relative high speed data entry, may make a "Voice into dataphone" system a preferred means of communication at some point in the future.

Cooperative Composition

Computer conversation is essentially a written form of instantaneous communication, and conversation is not the only conceivable application of such systems. Instantaneous written communications might also be productively applied to a form of communication that has no analogous traditional media. Cooperative composition is an interactive medium that extends computer conversation by allowing interactants to work on a project together.

They might, for instance, write a document together, build and test assumptions within a mathematical model, draw a picture, or even act as a team in reading an interactive novel. Each interactant would have the ability to add to and modify the document at any point at any time. This would inevitably lead to floor fights and other synchronization problems that would have to be solved by the interactants and, perhaps, some software intelligence. It could, however, change the nature of joint authorship by allowing two people to literally work on a document together.

What is most interesting about this mode of communication, aside from its potential productivity benefits, is that the very act of creating and editing a document can become a communication process in and of itself.

Computer Conferencing

In the world of traditional communication media, the conference is not a medium. It involves formal presentation (public speaking), conversation (face-to-face), and small group discussions, often in something that approaches equal portions, but it is best described as a genre, a combination of several media towards an end.

Computer conferencing, on the other hand, is a medium: one whose structure has almost nothing in common with the structure of real conferences. There is usually no schedule. People read and append from wherever they are at their own convenience. There is often no set agenda beyond a statement of what the conference is about and where discussion cannot go. The agenda is set by the interests of the participants, and the discussion goes where those interests lead.

The structure of a computer conference is most akin to the structure of a small group discussion. A group of people discuss a topic, generally without benefit of an accompanying formal presentation. As in any small group discussion, the tone is conversational and the participation varied. Some participants will only contribute once or twice, some will contribute a great deal, and some will just sit back and listen. A transcript of a longish computer conference will usually show evidence of many of the activities that characterize small group communication, including power struggles, facework, status seeking, leadership, and attempts to find common ground and even consensus. Indeed, a typical computer conference transcript might easily be mistaken for a transcript from a small group discussion.

But a computer conference is not a small group discussion any more than it is a conference in the conventional sense of the word:

Neither the size nor the speed of a typical computer conference should be overemphasized. The size of a computer conference is only apparent if you really look. They tend to feel like small group discussions even when hundreds of people have contributed and thousands have observed. And the scale on which a computer conference might be regarded as slow is a highly relative one. A few appends a day can be very fast indeed when:

It should be noted. moreover, that a conference will occasionally break from the crowd and attract a great deal of interest over a short period of time. Such forums may attract dozens of appends each day for a while.

The big advantage of the size and speed of the computer conference is the richness that results, and in this respect the computer conference is similar to a real world conference. Real world conferences are places where people gather to take advantage of the rich combined experience of many other people. The same is true of computer conferencing. To achieve this richness, a conference must both attract many people and give them time to express themselves. In their own way, both kinds of conferences succeed.

It should be noted that computer conferences come in two distinguishable flavors. Closed Computer Conferences are limited membership affairs, frequently set up "by invitation only". The conference has to know who you are in order for you to participate. Open computer conferences, on the other hand, are open door affairs to which all are welcome. If you can send a message to the conference, you can participate.

Each form has its advantages. Open conferences can attract large numbers of participants and a tremendous richness of experience. Closed computer conferences, on the other hand, can instill a feeling of commitment on the part of participants that assures ongoing participation. Thus while a closed conference has a smaller group of participants, it may grow faster.

Summary

These fifteen computer media are hardly an exhaustive set. We have barely started the task of exploring the potential of the computer as a mediator of the human communication process, and one suspects that the media outlined here are primitive by comparison to the kinds of computer media that will evolve in the future. The human imagination is already hard at work in this area, and that imagination already projects what may be the extremes of what computer-mediation can accomplish. At those extremes, however, people can communicate with the computer, and each other, at the speed of thought. Indeed, at the true extremes, people are able to transfer their intelligence directly to the computer, and actually touch each other's thoughts.