Alexandra Wilkis Wilson and Alexis Maybank. Larry Busacca, Getty Images

It all started with a Zac Posen sale.

The founders of Gilt Groupe Alexis Maybank and Alexandra Wilkis Wilson admitted that waiting for sales when the site launched its first "sample" sale was nerve wracking.

"We hoped people would shop, we hoped we'd make a ninth sale," Maybank told AOL Small Business, "and eight hours into it, we sold out entirely."

The former Harvard classmates started the shopping site just over three years ago to mimick the experience of shopping at an exclusive sample sale. Only "members" can shop sales on the site and each sale only lasts 36 hours, to create the feeling of customers getting something special that not just everyone can get.

And the offerings have expanded to include a wide variety of products, Current sales include Cupcake Stop cupcakes (and truck rental!), KORS Michael Kors shoes, Gerren Ford clothing, Hanii Y clothing, Kenneth Jay Lane jewelry and much more.

What started as an idea is now turning into a multi-million dollar enterprise that has spawned sub sites (for men, children, home furnishings and even Jetsetter for travel), made its first acquisition (of San Francisco-based deal site Bergine) and inspired others like RueLaLa and even eBay Vault to launch similar sites.

"At this point, there are many people pursuing the same idea -- flash sales," Maybank said. "It's flattering to see. It means something's working."

See Alexis and Alexandra's video telling the Gilt Groupe story on AOL Small Business's "My First Million" feature.