With more and more Irish households connected to the Internet, parents, many of whom are net novices, fear what their children might encounter. When children have all that extra surfing time during the summer holidays, opportunities for problems increase.

The good news is that the Internet can be both educational and a lot of fun. However, recent US studies show that one in four children encountered unwanted pornography on the Internet and one in five was exposed to sexual solicitations in the past year.

An interest in rabbits, for instance, might lead to a child putting the word bunny into the search line. This can lead to Playboy's website with just one click.

Dangers do not just lie in obvious sex sites, however. Even an interest in playing board games over the Internet can lead to difficult-to-judge situations for children. The 10-year-old son of Dr Lynda Tenhundfeld, a child psychiatrist with Georgetown University in the US, had just such an encounter while playing chess with a stranger through the web, when the person with whom he was playing asked for his name, age, where he lived and where he went to school.

"He started giving his name and age and then came to me," Dr Tenhunfeld told the Washington Times. "He typed back: `I am not allowed to tell you that.' The person asked why? My son said: `My mom told me not to.' The person typed back: `Your Mom's a smart woman' and went off line."

While it is very difficult to trace a specific user to their house through Internet use, people's use of the Internet can be traced back to their computers by means of "cookies" (indications of the user's previous patterns on your hard drive). This is how amazon.com knows to greet you by name when you go to its site and how it can make personal recommendations based on your previous purchases.

Devices known as filtering software 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.

While most of the available research into children's use of the Internet has been carried out in the US and UK, in Ireland the children's agency Barnardos and eircom.net have joined forces to produce a booklet called Family Guide To The Internet, which is available free through Barnardos and Eircom offices.