Before apparel became a $55 billion category for e-commerce, critics warned that people would never shop online because they want to try things on. Tony Hsieh and Zappos led the charge in proving them wrong by offering free returns and exchanges. That’s become the industry standard in e-commerce, but it has costs companies oodles of money in shipping as a result. Forty percent of online clothing purchases are returned, according to a 2013 Credit Suisse study. Fitbay, a young social shopping startup based in New York, aims to help people shop more confidently online, even if they have abnormally long torsos.

Like many startups, the idea sprang out of a frustrating experience from its founder. Christian Wylonis is 6’2”, a fairly average height in his native Copenhagen. But he has an “abnormally long torso” and always struggled to find shirts that were long enough, he says.

He built Fitbay to solve that issue by allowing people to shop based on their body type. The “dress for your body type” feature has been a staple of women’s magazines for decades. More recently, Drs. Phil and Oz have turned the concept of apple and pear-shaped bodies into multivitamins and diet guides. Fitbay builds on the idea by pairing people with “body doubles” who share their height, weight and body shape.

On, users identify their arm length, torso length, and shape (hourglass, pear, cone, apple, or straight for women; broad, column, oval, triangle or muscular for men). They’re shown clothing, Pinterest-style, from Fitbay’s database of two million items, all chosen and reviewed by their body doubles.

The company has operated in private beta for three months, adding tens of thousands of users and growing by 110% each month. It opened the site to the public yesterday.

Fitbay’s consumer-facing service is meant to help people who don’t fit perfectly into standard-sized clothing. But it’s also interesting to online retailers. Currently the company is making money on affiliate fees, where e-commerce sites pay Fitbay for any sales it drives.

Wylonis believes these sites would also be interested in the data Fitbay collects. For example, Fitbay knows the favorite brand of every different body type, and it knows which brands do poorly with “the fringes” of, say, very tall or very short shoppers. Women between 5’9″ and 6’1″ with a BMI over 32 tend to favor Old Navy, for example. Meanwhile, H&M is only popular with women of average height and weight, and Zara is most popular with cone-shaped women. For men who are oval-shaped (read: not in shape), Nike is most popular. Men under 5’9″ with a BMI below 16 prefer Aeropostale; larger men wear more Levi’s. Wylonis says this information would help brands decide whether they are serving all of their potential customers and should expand into petite or plus sizes.

In addition to its data, Fitbay is developing an open API so that online retailers can integrate with its recommendation engine, giving them the ability to show shoppers the most flattering items for their body type while they shop on a retailer’s site. “We want to become the global authority at doing this,” Wylonis says.

To help it expand, Fitbay has raised $2 million in new seed funding from Steadfast Venture Capital and Creandum, a Stockholm-based firm which was an early backer of Spotify. Now that the twelve-person company, based in New York, has exited beta-mode, it will focus on user acquisition.