"I bought [SportsMemorabilia.com] and then realized that I know absolutely nothing about sports," says Jesse Stein (above), who brought on Stefan Tesoriero (pictured below) as CEO and became the non-executive chairman. Courtesy Company

When Jesse Stein first purchased SportsMemorabilia.com in 2006, it wasn't much more than a parked domain with sponsored links netting its previous owner a couple hundred dollars a month. In just six years Stein turned it into a recognized retail brand with more than 450,000 products from across 13 sports--taking in $19.5 million in 2012 and earning a three-year growth rate of 270 percent.

Indeed, his Coral Gables, Florida-based SportsMemorabilia.com is one of the companies vying for a spot on the 2013 Inc. 5000. As applications arrive, we thought it would be worthwhile to shine a spotlight on some of these fast-growing private companies. (For more information and to apply, go here).

Stein, a serial entrepreneur and Wharton graduate, was inspired to buy the domain after attending a Las Vegas conference that suggested there was money to be made in e-commerce sites with "category killing" domain names. Stein began pursuing some 200 category-defining domain names--such as hobbies, biking, and boating.com--with the hopes of turning the ones that showed potential into e-commerce empires.

SportsMemorabilia.com was the first one of these killer domains that looked promising, so Stein purchased it for $12,500 and set about transforming it into a fully functioning website where customers could buy authentic, signed sports paraphernalia.

"I bought it and then realized that I know absolutely nothing about sports--and that was going to be a serious problem," says Stein, who brought on Stefan Tesoriero as CEO and became the non-executive chairman of SportsMemorabilia.com. Tesoriero had extensive sports marketing experience with the New York Islanders.

"I've always had this policy of hiring people who are much more talented than I am and then stepping out of the way," Stein says. "So I gave a very significant slice of the equity to the top 10 executives, and basically said, 'Guys, this is your business now. Run with it.'"

Stein realized that his competitors in the sports memorabilia industry had not yet woken up to the reality of the Internet, and with background in SEO, he instructed Tesoriero that the first step for the company was Google-rank dominance over its competitors. But rather than pursuing the typical metadata strategy, the company went for something more organic.

“We started the company by creating content that was meant for actual human consumption--not just stuff that was meant for Google,” Tesoriero says. “We researched the memorabilia industry and wrote articles on the various nuances of collecting and athletes. I conducted a lot of interviews with fan sites about products, players, and what people were looking for at the time. People starting linking to our content and Google started to give us credit and rank us accordingly.”

During this process, the company began building relationships with vendors and producers of signed memorabilia--something that Stein said came very easily with such a category-defining name. SportsMemorabilia.com would index the inventories of their vendors on their website, and the company and the vendor would get a cut with each purchase.

In 2011, the company began purchasing and storing its own merchandise in-house. But Stein says that, where its competitors get obsessed with athletes and memorabilia culture, SportsMemorabilia.com makes its purchases based off of complex forecasting analytics. For example, it'll buy and store say 50 signed Kobe Bryant basketballs for the first quarter of the year because its algorithm has predicted that 50 is the most likely quantity the company will sell in that given timeframe.