Robertson has trodden an unusual path in spreading the ASOS name. Although it's now an established pure-play etailer, with celebrity endorsements and millions of visitors to its site every month, the brand has predominantly been built offline, rather than on the web.

"We had £2.3m at start-up, which really isn't much, so we did the same cheap and dirty things that everyone at the time did, starting with affiliate marketing and PR," says Robertson. "We then ran full pages in magazines like Heat and Grazia. Although we have good brand awareness now, it has taken six years to get to that stage. Ironically, we've gone from being an online-only brand to moving away from online marketing. For example, we canned our affiliate marketing campaign three months ago."

For Robertson, affiliate marketing ticks the value box but doesn't build up the brand's image in any way. In contrast, coverage in a glossy magazines is a recipe for success, he says - one small link to the site can drive sales faster than most forms of paid advertising.

But he says the web still has an important role to play. "I'm not saying we couldn't do more in the online marketing space. Next year we'll reintroduce affiliate marketing, but as it should be. No silly commissions being paid to grubby little people in grubby studios growing income at our expense, getting in the way of genuine sales."

Things seem to be going well for ASOS. Sales were up by 80% prior to Christmas, with 710,000 items in 285,000 orders shipped through November and December. This is despite the December 2005 Buncefield oil depot explosion, which was 700m from ASOS's warehouse and caused almost £4m of damage to stock. "It was nothing you could ever predict, but where we are now shows the strength of the brand," says Robertson.

And that's a brand that was significantly different when it started out. Originally Robertson and his fellow co-founder wanted As Seen On Screen, as it was then called, to be an information-based site where people could find out about products they had seen on TV and in films.

"The idea was people would type in 'Mission Impossible' and up would come the products seen in the film, with the hope that Oakley sunglasses or some other brand featured in the movie would pay to be on the site," says Robertson. "But it become immediately obvious that they wouldn't. So we came around to the idea that the only way to monetise the site was to sell on it."

Between 2001 and 2002 the model shifted and As Seen On Screen was refashioned as ASOS. The change in focus has been for the good, and now the brand is being seen on screen itself. It recently sponsored America's Next Top Model on UK Living, the first TV spot ASOS has ever run. This includes an SMS campaign, where viewers can text to ASOS and receive a unique discount voucher. "That's gone really well," says Robertson, "but we're just playing with it as it'll always be the icing on the cake.

"TV sponsorship is cut-through. It's establishing ASOS as the online fashion retailer. You're not going to do that with a few banners going around the web. You have to get to critical mass. And we knew from the girls working here that this show isn't just relevant but a real favourite and a good place to be."

One thing that interests Robertson has been the development of magazine and content sites online. The last 12 months or so have seen many of the big publishing houses, such as Condé Nast, pushing their brands on the web. Indeed, ASOS is one of the brands to partner Condé Nast within Stylefinder.com, the celebrity fashion site which launched this week.

"We'll certainly revisit a lot of the content sites now," says Robertson. "The other magazines have really upped their ante, and we're really happy for ASOS to sit alongside them."

ASOS is also a publisher itself, launching its own monthly magazine last September. Next month the magazine will increase its size and print run. Robertson says the magazine was born out of simple marketing economics - it's a cost-effective way to put the ASOS brand into people's hands. Editorial crossover between the magazine and ASOS.com is strong, but Robertson says that recommendation is much more important than user-generated content.

"Bringing in aspects of user content isn't a priority, selling the right product is," he says. "Yesterday I sold 800 units of one dress, and no amount of UGC is going to do that for me. If we can sell 800 of the same dress in one day then there are clearly people emailing each other, telling their mates that the dress is here."

Robertson remains committed to building his online brand through offline channels. Despite the catastrophic start to 2006 post-Buncefield, the company is back on its feet, he says. "Things are looking great. We're selling more than ever, the brand's getting recognised by an ever increasing number of people, and our magazine is about to go up from 60 pages to 100."

And he isn't fazed by the competition. Last year Top Shop revealed that it wanted its site to become the second biggest store after its Oxford Circus flagship. Robertson questions whether this is ambitious enough.

"Everyone's patting themselves on the back saying their online store is going to be number two or three compared to in-store. But of course it is," he says. "What you have now is one store that's open to the entire UK population, rather than the 40 or 50 people who might be walking past it on the high street.

"That demonstrates that a lot of these high-street stores are fundamentally flawed in terms of their business model," he continues. "A store like Top Shop Oxford Circus is a dream ticket - I wish I had one - but that's a different story. For the other stores around the country, it shows that their model is inefficient."

CV

Name: Nick Robertson

Title: CEO, ASOS

Age: 39

Career: 1987-91: Media planner/buyer, Young & Rubicam; 1991-95: Associate director, Carat UK; 1995-2000: Founder and MD, Entertainment Marketing; 2000-present: Co-founder and CEO, ASOS