How sad is this? I'm watching people logging on to the internet. I'm staring at two men in their mid-20s and two slightly older women, who are all staring into computer screens. This is the virtual world's equivalent of watching grass grow - and I'm finding it interesting.

But that's maybe because of the voyeuristic thrill of it all. I'm standing, observing but unobserved, behind a huge 12ft x 6ft two-way mirror. It looks like a lightly electrified cinema screen, set before two rows of tip-up seats and a well-stocked fridge for the use of advertising executives and clients as they watch their guinea pigs.

But we are not here for voyeuristic thrills. The whole purpose of this session at the offices of the leading advertising agency BMP in Paddington, London, is to get rid of the idea of the internet as something that is sexy but aimless and unproductive. Gone are the days of companies saying "we've got a lot of money and this is a whole new sector, so let's suck it and see. Whoopee!"

Now it's path-to-profit time, and the internet industry is learning that if it doesn't work, it doesn't eat. Advertising, in particular, has to be seen to work to justify the spend from a marketing director's budget, which is why I'm behind the screen, watching the consumer group brought together by Billco, the new-media agency subsidiary of BMP.

The old economy and the economics of the corner shop have caught up with, and publicly disembowelled, last year's cyperbole. The businesses and ideas left standing now that the hype has exploded have to satisfy some very serious, old-economy tests. BMP is generally regarded as being a very serious advertising agency, and Billco's managing director, Alison Parker, is leading the consumer group through a classic qualitative research session.

Parker asks the group about their general use of the internet and whether they use sites offering holiday services (the client is in this sector), then asks them to go online and play with the site. The users have the classic technophile profile. They use the research engine to squeeze comparative value out of the market. And they are not afraid to send their credit card numbers out into the ether. One of the women used a shopping site to buy a Dyson cleaner at a discount of £60 on its high-street price, and had the appliance delivered within two days. One of the men has used the net to search out the best price for a car. Both men and one of the women go online for football news, and everyone agrees that Amazon has a good site - especially if you belong to a book club and want to crib a review.

All this confidence and enthusiasm, not to mention the exquisite bits of prawn toast, are reasons to be cheerful. But there is, of course, a downside to this consumer sophistication: "I never give real information," says one of the guys. "I've got a duplicate email that's related to me, but gets all the dross that you can get from the internet. I bought some car insurance over the net, and then got bombarded by Norwich Union trying to sell me personal loans. I'm also pissed off about not being able to unsubscribe from lastminute.com. I've tried and tried, but I just can't get rid of them."

Leaving aside the possibility that the market may well solve his lastminute problem for him in the next few weeks, the idea of consumers setting up virtual doppelgangers on message systems like Hotmail and Excite is depressing news for all those carefully targeted mailshots and cleverly calibrated marketing strategies. It's also a bit depressing for the likes of Hotmail to realise that so much of their traffic is just dross for decoys.

This is the heart of the problem - so much dross, so little gold. The conversation on the look and feel of the site Billco is testing is particularly interesting on this point. Those still enthusiastic about the internet - and I am one - often make the comparison between today's online industry and the early days of television. When ITV was launched, many people felt that screen advertising would never be taken seriously. It is now of course the single most important advertising medium. So the obvious parallel to draw is that as consumers become better acclimatised to and more trusting of their PC screens, online advertising will, at the very least, become far more important. But anyone who thinks that golden scenario is just round the corner is a couple of pixels short of a liquid crystal display. The quality and power of the computers used to go online varies massively. Given the kit most consumers have in their homes and offices, online advertising is destined to remain the poor relation of television for some time.

"At the risk of stating the screamingly obvious, a banner ad on a website is not going to have the same impact as a 60-second television commercial," says Parker. "What's important is that what's on the internet is integrated into the brand's overall marketing strategy. The website is another opportunity for a brand to enter into a relationship with the consumer, so the language, colour and functionality must be right for the brand. The site for Polly Pocket is very pink and playful, whereas the site we built recently for Haystack (an online media-agency search facility) is about professionalism and speedy results - in red and black. If a site doesn't give users what they want, they'll turn off."

The consumer group has now done just that. It expresses a preference for one of the sites competing with the client's. This one is "friendlier", more "human" than the client's site. As a consequence, the group is less resistant to "paying". They see themselves paying with time, not money. The alternative currency, of course, is information. And it's now clearly established that unless the registration process is very subtly handled (let the user in to play around straight away, and keep the questions as short, few and easy as possible) much of that coinage will be counterfeit.

Counterfeit details or not, the consumer research is real. Who knows? If the advertising industry really does find a way to make the new economy jump through the old economy's hoops, we might one day end up with new media companies that actually do boring, old-economy things like make money.