Janet Street-Porter: Show some responsibility, eBay

I've sold a Swatch watch for £500 and some dinner plates shaped like fish for a fiver each

When Bob Geldof called eBay an "electronic pimp" for allowing tickets for the Live8 concert to be sold on their website, he was the first high profile person to signal that the world's favourite auction house might have a down side. Once, we got off our backsides and scoured flea markets, charity shops and antique fairs for bargains at weekends. These days, we sit at home each evening and log on to eBay and, as a result, our rear ends are getting broader as their profits expand at an exponential rate.

The company will be five years old in the UK this year, and during that time there has been surprisingly little criticism of the way that they operate. Last year, eBay engaged a public relations organisation and members of the press were sent CD-Roms and lavish press releases extolling the virtues of buying and selling online.

By the end of this year, the company's revenue is expected to be more than £3bn, and in 2004 it made roughly £100m profit, an astonishing increase of 77 per cent, partly down to its huge success in Britain. eBay is the new internet shrine at which we all worship, the largest shopping mall in the world.

In 2005, it is expected that eBay will be the third dotcom company (after Google and Amazon) to generate more than $1bn (£549m) in three months, and it's already twice as profitable as Amazon, with no need for warehouses or storage units, simply acting as a facilitator by taking a cut from every transaction.

Until the Live8 scandal, there were few categories of goods which are banned on the website (firearms, pornography, drugs, alcohol, tobacco, fireworks and Nazi memorabilia); but with 150 million listings worldwide, (5 million added daily), eBay is becoming impossible to police. Last December, the chief executive of one of their subsidiaries in India was jailed for a week after police discovered a pornographic video was being sold on the site in a case which could have repercussions around the world. When does responsibility start and end in cyberspace?

This exponential growth of internet buying and selling has seen people give up their jobs to become online dealers. Where once we would rely on our senses, by viewing, feeling and touching objects in order to purchase them, now we increasingly rely on a digital photograph and a couple of lines of description. We offload unwanted Christmas presents, antiques we've fallen out of love with, dresses that don't fit and old magazine collections we don't have room for. There has been a growing number of complaints of fraud on eBay - fake designer bags for example - but tracking down internet crooks can be extremely difficult.

Then there are the crazies and the cranks with no intention of paying up. A 13-year old boy was found to have bid £2m for a 1971 Corvette and an office building in Florida, and only last month an unemployed teenager from Wales was convicted of obtaining £45,000 through selling non-existent electrical goods on eBay. Even when on bail awaiting trial, Philip Shortman resumed his fraudulent activities, claiming he was "addicted" to eBay. Even more amazing was the news that he had started his internet career at 16, having been excluded from school. The company apologised to his victims - but told people to read carefully the terms and conditions of sale - in other words, it's not their responsibility.

When the Inland Revenue announced that they were interested in the huge sums being made on eBay, the company merely announced that transactions were "private" - ie not their business, providing no more than links on the site to information about tax.

Criminals are known to have infiltrated eBay, using software that records your personal details, by claiming that the successful bidder for an item has dropped out, and offering it to you. You are told to send money to an account that has nothing to do with the original vendor.

"Matrix auctions" are when items are offered for sale on eBay, but in reality all you are buying is the information on how to buy an object. It is easy for sellers to place bids on their own merchandise, ramping up the price, and writing glowing testimonials. eBay routinely offers for sale brand new merchandise you can buy from the manufacturers at a far lower price - from digital cameras to mobile phones to computers. Suckers looking for bargains cough up.

Then there are the tickets to concerts and sporting events sold on eBay at inflated prices, when the actual event hasn't even sold out and you could simply ring up the box office and get a better deal. For every football shirt or CD sold by an honest member of the public, there is a professional gambler making a fast buck. Which? reckons there are 200 fraudulent transactions a day on eBay in the UK, but in reality there are probably many more. And it is increasingly being used to dispose of stolen goods, from antiques to far more exotic stuff - recently, a prisoner's boiler suit and stolen ambulance equipment, including stretchers and resuscitation kits, were offered for sale.

We all love the idea of a bargain - even Cherie Blair succumbed, buying some red shoes for £10 and Disney videos, and being honest (or naive) enough to use her own name. I've sold Clarice Cliff salt and pepper sets, 1960s luggage, a Swatch watch for £500, and some dinner plates shaped like fish for a fiver each. But these are relatively mundane transactions compared to the man who recently offered a roll of toilet paper from the old Abbey Road studios stamped with the words EMI Ltd, hoping to cash in on the Beatles connection.

In our minds, we convince ourselves we're recycling - no one likes the idea of admitting they're dealing for profit, pure and simple. In our materialistic world, the companies who provide secure storage units are prospering as we accumulate more crap than we can ever use, and eBay is justified as a clever way of down-sizing, making life simpler.

But it is curiously addictive, and for every handbag or set of hub caps you offload, you have to be enormously strong willed not to shell out for a cheap washing machine or a Prada vest. eBay taps into something loathsome about 21st-century consumers, which is our inability ever to shout the word ENOUGH! Now, goods produced in the name of charity even end up being auctioned for a profit - eBay has done nothing to prevent the sale of Make Poverty History wristbands. Presumably it's just another "private" transaction as far as they are concerned.

Mr Geldof was right to signal that, somewhere down the line, the owners of eBay might like to consider their responsibilities along with their giant profits, and perhaps contribute something back into the Third World which is so poor that it has nothing whatsoever to auction online.