NEW YORK ( TheStreet) -- I'm an insider. An email has arrived with an exclusive deal on some fine jewelry by Movado ( MOV) and reduced-price handbags and shoes from rock star Gwen Stefani's line, L.A.M.B. (It stands for Love Angel Music Baby, in case you didn't know.) I can also buy Tateossian cufflinks for my man at lower-than-normal prices or reduced-price travel to San Diego and the Hard Rock Hotel -- if I act fast enough. The sales expire in a few short days, and there are a limited number of items. These are the kind of perks you can get when you know somebody, and that somebody vouches for you to Gilt Groupe. There are 3.5 million of us insiders on Gilt.com. Gilt has created a following based on the allure of high-end retail apparel, home goods and travel at affordable prices, and sold it with the feel of word-of-mouth referrals as opposed to advertising. The company positions "members" to feel like they are part of an exclusive club -- something that might seem like just another online-marketing ploy, but has proven to be golden for Gilt. Four years ago, it was but a glimmer of an idea in co-founder and CEO Kevin Ryan's mind. But since its official launch in November 2007 as a women's end-of-season flash sale site, the company has grown from a 10-person team to more than 600 employees (and growing). Between its expansion to men's discount, home goods, children and travel under the Jetsetter label, Gilt membership has surged, bringing in more than $400 million in revenue last year. "I don't think it's different for any business; your product has to be really good," Ryan says in an interview with TheStreet. "There is a fundamental trend of more people buying online," Ryan says. "The product is different. There wasn't an easy way for you to go to a sample sale, either because you don't live in New York or because you have a job and can't leave at 5 p.m. to go to a sample sale. It's all about creating a better product, a differentiated product, and that requires great people and good strategy."