The Internet, while being increasingly recognised as a major tool for educational purposes, still has an element of fear attached to it in relation to what browsers may come across, accidentally or otherwise. When the browsers in question are children, the apprehension increases. Recent US studies show that one-in-four children encountered unwanted pornography on the Internet and that one in five was exposed to unwanted sexual solicitations in the past year. So caution and vigilance on behalf of anyone supervising a child's use of the Internet is not only to be encouraged, but should be a matter of course for any parent or teacher operating in this capacity.

Particular care needs to be exercised when putting words into a search engine and clicking into the site suggestions this leads to. Even a seemingly innocuous search, such as someone interested in US politics typing "whitehouse", can lead to hard-core pornography sites. This happens because of what are known as "keywords".

Any website can arrange with search engines that the inputting of certain words will lead to a suggested link to their site. In the case of the Irish Times website at www.ireland.com, for instance, the keywords include the names of Irish politicians and tribunals of inquiry.

There are dangers outside of obvious sex sites too. An area of Internet use that has been highlighted as suspect in US studies are "chat rooms". These are sites, or areas of sites, which allow people to have a conversation with each other in "real time". From a list of people seeking to have a discussion on a particular topic, homework for instance, you can pick someone for a private chat.

While many of these services are entirely above board, and indeed helpful to the user, there are others which are not as well supervised by the site owners as they should be.

This can lead to, for instance, paedophiles pretending to be of the same age as others using a particular site.

After engaging a child or teenager in conversation for a while, they may then start to ask personal questions, such as what school they go to, their full name, age and home phone number. They may also try to arrange a meeting with the child.

The way to minimise the risk that a child will encounter such sites is to agree rules of use for the Internet. To this end, the children's agency Barnardos and eircom.net have jointly produced a booklet called Family Guide To The Internet, which is available free through Barnardos and Eircom offices.

Also very useful for protecting children using the Internet are devices known as filtering software, which can block out inappropriate sites or blacklist addresses known to lead to pornography and other undesirable material.

The best known, and oldest, of these is Net Nanny - www.netnanny.com . Other examples can be found at www.familyguidebook.com.

The Internet is a great tool, and parental vigilance will help ensure that children enjoy and get the most out of it.