When Miss Boo starts flipping her ponytail and batting her eyelashes from the lime-green pages of Boo.com this summer, she will represent one of the biggest, boldest bets in the short history of electronic shopping.

Miss Boo is a sassy cartoon shopping robot dreamed up by two 28-year-old Swedish entrepreneurs to guide customers through their global Web sportswear store. Launching in August, Boo.com has financial backing from a Who's Who of European fashion, from the Benetton family to Bernard Arnault, whose French company owns Louis Vuitton and Christian Dior.

With its swirling 3-D shoes, virtual dressing rooms and animated models wearing click-and-sizzles, the site could define a whole new generation of high-end retailing on the Internet. But if it fizzles, Boo.com could send investors scurrying back to offline retailing and give greater impetus for e-tailers to focus on price and no-frills products.

Either way, Boo.com is an experiment worth watching because it cuts to the core of retailing's struggle to reinvent itself online.

"What's different about Boo.com is that we are bringing lots of the style and fashion back into electronic commerce," said Ernst Malmsten, the company's chief executive and co-founder. "We are also offering a global selection and many things that are very hard to find in traditional stores."

Malmsten and his partner, former model Kajsa Leander, persuaded about two dozen manufacturers to let Boo.com sell everything in their sportswear lines. Customers will be able to find cult-chic streetwear from Cosmic Girl, cool jackets from the North Face, street-hip activewear from Puma. To encourage shoppers to take a chance on clothes they can't try on, the site will accept returns at no charge and include return shipping labels with each package. Shipping is free in the United States, with delivery guaranteed within five days.

Boo.com's founders believe electronic commerce is ready to move beyond the first-generation of price discounts. Boo.com wants to use the cost savings from the Internet's efficient distribution system not to lower prices, but to build interactive tools that mimic the touchy-feely experiences and glitzy merchandising that have been so essential to real-world shopping.

Many of these techniques also are being developed individually by a few clothing manufacturers who are developing their own online stores, from Levi's custom jeans-fitter to Eddie Bauer's virtual dressing room and Land's End's personalized virtual models. And while most American department stores have been slow to pump money into their Web sites, they almost all have major projects underway that are expected for the big fall shopping season.

Few, however, are as ambitious or novel as Boo's. The site will provide detailed information on how sizes vary by brand, with plans eventually to record and scan body measurements to make size selection even more precise. A companion e-zine called Boom will offer stories with music, videos and animated models. Readers will be able to click directly on shoes, jackets or shorts worn by the "boo-tiful" people featured, either to take a closer look or buy items on the spot.

The bet is big. Malmsten declined to say how much money Boo.com has raised in funding rounds led by J.P. Morgan, but it is likely well over $50 million. "I think this may be the largest Internet start-up ever," Malmsten allowed.

Malmsten and Leander jumped into the $60 billion global market for sportswear last year after selling the European online bookstore they had founded in 1996. Although clothing sales have been slow to migrate online, Forrester Research reports that situation is changing fast and predicts 7 percent of the $20 billion apparel sales market could be online by 2003.

Since securing funding eight months ago, the Boo.com team has recruited more than 200 employees; opened offices in London, Stockholm, Munich and New York; set up distribution centers in Germany and the United States; and built real-time electronic links to clothing suppliers so Boo.com will automatically know what is in stock and not display items requiring back orders.

The technical terrain has proved so rocky that the launch has been delayed repeatedly. Its demonstration at www.boo.com has shown a worrisome knack for crashing Web browsers.

Glitches are hardly surprising, though. The site aims to let customers rotate three-dimensional images of every single item for a closer look at details--all the way down to sneaker glue. The 3-D imaging requires taking 18 to 24 photographs of each item, then using special software to stitch them together.

Customers also will be able to drag clothes into virtual dressing rooms and drop them on 3-D mannequins to see how they look together. To get a second opinion on an outfit, shoppers can e-mail their dressed-up mannequin to friends.

Such glitzy features are how Boo's young founders managed to sign up well-known clothing manufacturers who had turned down many other Internet entrepreneurs. Manufacturers, after all, have invested billions of dollars in creating brand names that are meant to stand for a certain shade of beauty--a particular lifestyle or image they want consumers to identify with. Now these kingpins are hungry for tools to help them carry their lucrative fashion kingdoms into cyberspace.

Over the past two years, manufacturers have watched with unease as a new electronic retailing environment has emerged, one that shows little respect for the fashion world's obsession with glamour. Instead, e-tailing so far has put a premium on functional traits like price, size and database searches. The most successful commercial Web sites have been text-oriented, describing rather than showing products, in large part because images take so long to transmit over today's Internet lines.

But Boo.com is positioning itself for a future when people are expected to access the Internet through faster connections. Its big bet is that when that day arrives, consumers will be willing to pay extra to e-tailers who help them find the romance, glamour and fun they crave in their lives. That, after all, is what fashion is about.

It is not a bad bet. People have been paying a premium to the consumer mass-marketing machine for psychological pick-me-ups for most of this century. While the Internet is changing many things, human nature is not one of them.

Leslie Walker's e-mail address is walkerl@washpost.com.

TechThursday columnist Leslie Walker will host a live Web chat today at 1 p.m. with David Gladstone, vice president of American Capital Strategies. He'll discuss ways to handle financing strategies in small businesses. To participate, go to www.washingtonpost.com.

CAPTION: Ernst Malmsten, left, Kajsa Leander and Patrik Hedelin are founders of the online clothing store Boo.com, which opens in August.