The arrival of every new mass medium this century has been accompanied by arguments and commentaries on their impact on the quality of life, on culture and on democracy.

Cinema, radio and television were all regarded at some time - and are possibly still - as threatening family and community life by killing conversation and reducing direct interaction between people. It is often claimed that overreliance on these media would stifle traditional forms of culture and the arts and that, in the wrong hands, they could be used for malicious and propagandistic purposes.

With the rapid development of the Internet, the same perspectives are being argued and the same prophecies being made. The Internet is promoted strongly by powerful commercial interests selling computers, software and communications services and by advocates who see it as an exciting departure in free and open communication. Those who are worried about the Internet's lack of controls and its use by political extremists, pornographers or paedophiles tend to be dismissive of its potential worth.

The Internet is widely seen as a technical "fix" with far-reaching consequences for business, education, entertainment, and the conduct of democracy. The rapid increase in the Internet-user population and the spread of Internet services to almost every country of the world is the basis of claims from some quarters that a new global community is being formed. By ridiculing the more outlandish claims, we may miss some of the things that are distinctive about the Internet as a medium. These boil down to 10 propositions, each of which has something to support it, but also needs to be qualified - and each distinguishing feature has disadvantages as well as advantages.

the Internet has no central control

The Internet has developed with many heads, as a means of protecting it from attack. For most of its existence, it has been mainly a means for researchers to share information. Operating on the basis of trust, universities and other research centres have developed different services in different places. Information gets around by many different routes.

This many-centred form means it has become a means for holding centres of power to account. It has also been the medium for subversive and other anti-state activity, for hackers to gain access to secret military information, for rebels in the Mexican province of Chiapas to send out news of their uprising and for right-wing militias in the US to make propaganda and recruit.

The Internet may not be able to keep this distinctive form. Some people believe the present commercialisation of the Internet brings with it the risk that it will come to be dominated by the corporations which dominate the world's media, computer and telecommunications industries.

the Internet has no censorship

Mainly as a consequence of the lack of central control, there is not - and there cannot be - any global censorship. However, some authoritarian countries which have hooked up recently have restricted the connections between them and the Internet, allowing them to exclude certain kinds of content. The Chinese have not forgotten that news of the student revolt in Tianenmen Square first got to the outside world through Internet discussion groups. Other governments are more concerned with the use of the Internet for purposes they define as immoral or indecent.

The Internet is used for distributing pornographic and paedophiliac material. So too are the post and printed magazines - but it is possible to communicate material over the Internet which the laws of libel would prevent being printed and published in more conventional manner. Its international reach and the automated switching of information from one place to another make it difficult to know where and against whom legal action should be taken and heard.

Some Internet service providers voluntarily exclude material they do not wish to redistribute. Filtering software is also available for individual Internet users to prevent access to defined categories of information.

the Internet is inexpensive

By comparison with any other means, the Internet offers a much less expensive way of sending a message to Australia, looking up the Library of Congress catalogue or seeing what the English-language newspapers of Tokyo have to say about the collapse of Yamaichi Securities. Not everybody wants or needs to do such things - but it may be that the mere fact of being able to do them for the price of a local telephone call encourages such activity. To use Internet services requires having a computer and modem; the cost of these is beyond the reach of most households and many organisations in Ireland. With this equipment, individual Internet accounts can be had for about £10 per month, plus phone charges. Most of the necessary software is provided free or at low cost.

Because local calls are metered in Ireland and searches on the Internet can easily run for a half-hour or hour, it is easy to double the size of your phone bill by using a line for Internet access as well as normal voice use. Initiatives are being taken to keep these costs down for schools. The same may need to be done at least for public libraries and for community and voluntary organisations.

All of this will remain irrelevant to the majority of the world's population who have never even made a phone call.

the Internet gives access to vast quantities of information

The Internet is often compared with a huge library, holding more information than could ever be held in a library full of paper. But no known library would want to hold the Internet's stores - a library's information is organised and classified; the lack of organisation and classification define the Internet.

The World Wide Web appears ordered, but there is much there that is, at best, trivial. Increasingly powerful "search engines" make it possible to trawl quickly through the material displayed on the Web and sent to discussion groups. But there is no guarantee that any of the information retrieved is accurate. Commercial plugs, extremist rantings and malicious messages appear alongside useful information.

More information is not necessarily better information unless we have the means of analysing and evaluating it. Acquiring these skills is at least as important as learning how to hook up.

the Internet gives access to info from many types of source

With the necessary technical and analytical skills, Internet users can open up a vastly wider range of sources of information than is available by any other means. It becomes possible to add new data and new insights to the material which, for example, the print and broadcast media make available. Newspaper readers can go behind the printed stories either to consult directly the sources which the journalists used or to look at the information available from those sources which were ignored (see below, left). Many discussion groups host lively, challenging exchanges which span different cultures.

But all Internet information can look much the same. Anybody can present themselves on the World Wide Web as an authoritative source. In discussion groups, the resolution of arguments may often come down to persistence rather than to relevance or truth.

Internet users can be producers as well as consumers of information

Many Internet services make it possible for users to contribute directly to the flow of information as well as to receive it. Anybody with access to the Internet, and with minimal technical skills, can contribute to discussion groups. With rather more training, it is possible to set up a web site. It takes yet further resources to maintain that site. The vast majority of readily accessible Internet material comes from organisations which are already geared to providing information (see `a day in the life', below).

Within those limitations, Internet users can be transmitters as well as receivers. In practice, few users contribute more than private email messages. Enough people do something more, however, to make the Internet a more diverse public communication space than any other mass medium.

Internet communication is rapid

Within minutes of the Louise Woodward judgment being displayed at the web site of a law journal in Massachusetts, it could be read by Internet users around the world - or would have been, if there had not been a power cut. In the same way, a message the same length as this article can be sent from Ireland to Argentina in minutes - but routes on the Internet can get jammed, services have to be maintained or upgraded, computers providing Internet services can crash and all of these things can mean either that messages go astray or take hours to be re-routed from one bit of the network to another.

While email users like to joke about ordinary post as "snail mail", web users sometimes refer to that service as the "World Wide Wait".

Internet communication is equally open to all

When we communicate directly, person-to-person, we get information about accent, age, status, gender and much else to make sense of, and colour, what we are hearing. Internet communication, on the other hand, appears to be more equal because one person's piece of computer text looks pretty much like another person's; some Internet users employ pseudonyms.

This should mean, for instance, that women meet fewer of the obstacles they encounter elsewhere to making themselves heard. But the Internet population is disproportionately male and middle class, and many women feel excluded by the language used and by other aspects of the Internet "culture". It is also perfectly possible to bully, harass and hector by email or on the Web, intimidating people from participating as fully as the technology seems to permit.

Communication is interactive

Any Internet user can respond directly to information received. Interactivity also takes the form of users choosing their own routes into, around and out of a web site. Here, the interactivity is a function of the design; many sites are set up to draw attention to ads or facilities for buying things on-line.

The ease of interacting with other Internet users can be the basis of often intense international debates but also of much trivial and irritating knee-jerk communication.

Internet communication takes many diverse forms

Communication by telephone is for most practical purposes limited to one-to- one; and print and broadcast media operate on the basis mainly of one-to-many. The Internet facilitates both these forms, as well as many-to-many and many-to-one communication. This has sometimes been seen as the Internet's capacity to build community and to allow for greater democratic participation: many-to-many communication might involve a topic of concern to a particular neighbourhood; many-to-one could be the lobbying of the local TD to ensure she takes up the issue.

In this last respect, as in others already mentioned, the key issues in determining how using the Internet may affect the quality of our lives are social, not technical. What we get out of more widespread Internet access - either in schools or in society as a whole - will be influenced by the measures taken to ensure equality of access, and training in using it effectively.

We should be concerned less about the impact of the Internet on society and more about the impact of society on the Internet.

If you're going on-line for Christmas, read media scope on January 7th for fun and useful Internet tips.