Perils and pitfalls that await the unwary on the World Wide Web

If, after much tweaking of wires and banging of keys, you've finally got the computer you bought for Christmas connected to the Internet, congratulations - your problems are just beginning. Charles Arthur, Science Editor, on what to beware when you're surfing.

A growing body of evidence indicates that the Internet is a terrific information resource - but that it is also increasingly the target for get-rich-quick schemes and scams aimed at the uninitiated.

For those who have barely stumbled onto the World Wide Web, a vital first stop may be a site run by a husband-and-wife team in the town of Olney, Maryland.

Called Scambusters, and located at http://www.scambusters.org it is dedicated to warning newcomers about the latest frauds - some very subtle - being perpetrated on the Net. They include sending people e-mail telling them that a bill is outstanding, and that the recipient must ring a number or else the bailiffs will be calling.

The bill is fake - but the phone number connects to a recording in the Caribbean, with charges which can be up to pounds 10 per minute. One of these companies used its connection through a British company, Demon Internet, and sent e-mails to thousands of Americans telling them to call a number prefixed with the code "809". While most ignored it, some did call and found themselves listening to a slow recording telling them their call would soon be dealt with. Demon cut the company off and is considering taking further action.

But those who have just logged on have one advantage: the people who send out such e-mail - known as junk e-mail, or more colloquially, "spam" (after the Monty Python sketch) - do not have your address yet. They can usually only get it if it appears in a Web page, or if you type it in to a Web page, or if you post your normal address in one of the thousands of discussion groups, or "newsgroups". Anyone considering doing that should look first at the information offered by the Scambusters on avoiding letting the "spammers" get your address - for once they have it, they will relentlessly send you details of pyramid schemes (illegal in the US and UK), multi- level marketing schemes (which are guaranteed to fail), and wonder products and share tips which will generally do exactly the opposite of what is forecast for them.

Another wrinkle to watch for is sites or e-mails which ask for your credit card or bank details. A number of Californians have recently been contacted with offers to take part in the "Nigerian bank" fraud - except they aren't told it is a fraud. The message says there is a huge amount of money for which they want to use your account as a stopping-off place, offering you a cut. In fact, if you give out your details, any flow of money will be out of your account, not in.

Yet the problem of "spam", both in newsgroups and e-mail, continues to grow. There are an estimated 13 million pieces of junk e-mail sent every day - each one imposing its cost on the receiver, rather than the sender.

The problem is worse with news postings. According to DejaNews, a US company based in Austin, Texas, which archives newsgroup postings, there are about 730,000 new "posts" every day, taking roughly 5,000 Mb (5 gigabytes) of storage - yet two-thirds of that is either "spam" (including pyramid schemes) or messages sent by systems administrators trying to remove those unwanted messages from the system.

"Newsgroups are a tremendous source of information and exchange used by over 24 million people around the world," said Guy Hoffman, head of Deja News. "Unfortunately, a small number of individuals and companies are abusing the Usenet to the detriment of everyone else."