The boom era of the Internet -- symbolized by such firms as Amazon, Lastminute.com and eBay -- will soon be a thing of the past unless coordinated action is taken to improve security, Microsoft has warned.
An estimated US$2.52 trillion was spent on e-commerce last year, and in a country just the size of Britain more than 11,000 new users come online every day.
But the information superhighway is becoming so choked by spam, viruses and fraud that some experts believe it could become "unusable," with trust in online retailers destroyed.
Ed Gibson, a former FBI special agent recruited to bolster Microsoft's security work, warned: "In five years, if Microsoft and other major players in this arena do not make a concerted effort to make the products more secure, the thing we call the World Wide Web and the Internet will not be as it is today."
An estimated 136 billion e-mails are sent around the world every day, of which 65 percent are thought to be unsolicited, or spam.
A large proportion of spam now contains viruses that use computers to distribute more spam without the knowledge of the owner.
In 2000 an estimated one in 2,500 e-mails sent to businesses contained a virus; now it is one in 43.
British businesses lost an estimated US$4.32 billion last year to cyber-crime.
Even Gibson, an expert in investigating international money laundering during his 20 years at the FBI, recently fell victim to an Internet scam.
He said: "All of us in the industry have to get the message across that as soon as we log onto this thing called the Internet, whether we are a business person or simply a four-year-old or a 94-year-old, we have opened up every window in the universe to our home."
He was speaking at the Westminster eForum in London as chief security adviser to Microsoft in the UK.
Other Internet security specialists believe that the spam crisis is urgent.
Richard Cox, chief information officer of anti-spam campaigner Spamhaus, said: "If you can't go to a website without risking your computer being compromised, if you can't open your e-mail box because so much of it is junk, what's left? In three years the Internet could be unusable."
Cox gave the National Hi-Tech Crime Unit (NHTCU) zero out of 10 for its performance in the fight against spammers.
"They have done absolutely nothing. We don't see that as acceptable. We believe the NHTCU has got to be targeted on what is a very serious crime," he said.
Sharon Lemon, head of the NHTCU, responded: "Spam circulated for the purposes of marketing or advertising can be annoying to some, but does not fall within our remit. Resources within the NHTCU are focused upon the types of high-tech crime which cause the most harm to the public and business."