One of the greatest assets an entrepreneur can have is the ability to sniff out an unmet demand. If you have that, and the money to capitalize on it, congratulations. You have the tools to create a new market.

One entrepreneur who qualified is Daymond John, founder and CEO of the clothing company FUBU, which helped establish a market for urban apparel. John, a panelist on the entrepreneurial reality show "Shark Tank," said his customers were always out there, but few saw them as a consumer base to be catered to.

"I realized that there was an opportunity when Cross Colors, Karl Kani and Walker Wear started to address this market," he said in an email. "I knew there was an overall movement being created and people would want to have more than one option."

Today, enough people wear urban apparel that one must conclude that John was right. But 20 years ago, it wasn't so clear, and he said that no matter how good your instincts are, creating a new market is always an exercise that requires taking a leap of faith.

"You can assume how great your product is," he said. "But until you actually go out and sell and people come back to reorder and reorder and reorder … you will never know if a consumer truly wants to reach in their pocket and buy your product."

Read ahead and find out about the entrepreneurs whose products created new markets.

—By CNBC's Daniel Bukszpan
Posted 21 Jan. 2013

Tuesday nights have more bite with back-to-back episodes of "Shark Tank" on CNBC,

Not every one wants to wear 6-inch stilettos. Many just want to be comfortable, but until 2002 they found themselves limited to sneakers and flip-flops. That changed when Crocs came along that year, and the unusual-looking ventilated foam clog became a surprise hit, seemingly from out of nowhere.

The claim that Crocs are unusually comfortable is not just an opinion. In 2006, The Washington Post reported that the shoes are made of a resin foam called Croslite, which the American Podiatric Medical Association said "warms and softens with body heat and molds to the users' feet, while remaining extremely lightweight."

Not everybody was sold. The shoes appeared on Time magazine's "50 Worst Inventions" list, and Maxim magazine said that "Crocs are not acceptable. In any color. EVER." in its list of the 10 worst things to happen to men in 2007. However, Crocs remained popular, and in 2011 the company reported reaching $1 billion in annual sales.

In a bygone era, those with home improvement projects didn’t have a lot of options. Paint and nails were easy enough to get from the local hardware store, but if the consumer had something more ambitious in mind, like remodeling a kitchen, it often meant hiring outside contractors, at great expense.

Enter Home Depot. It was founded in 1978 by Arthur Blank and Bernie Marcus, who wanted to create the ultimate one-stop shopping destination for do-it-yourselfers. Sales associates offered clinics to customers in such esoterica as laying tile or operating a drill, thereby putting the know-how in the hands of the customer.

This proved massively popular. The company went public in 1981, a scant three years after its founding, and in 2012 it reported $74.8 billion in revenue to the Securities and Exchange Commission.

Lane Bryant is the leading clothing company for plus-size women. Founded in 1900 by Lithuanian immigrant Lena Himmelstein Bryant, her first name was misspelled as "Lane" when she opened her first bank account, according to the Jewish Women's Archive. The name stuck.

While the company had always catered to plus-size women since its first store opened in 1904, it found dominance in the marketplace when it developed a progressive marketing campaign in the 1990s, according to the official website of its parent company Ascena Retail Group. Advertising "focused on the celebration and empowerment of women" by emphasizing the clothing from a fashion standpoint as opposed to simply focusing on size.

This strategy hit a chord with plus-size women, and today there are more than 800 stores in 48 states to serve sizes 14 to 28.

The Snuggie is not the only "sleeved blanket" out there in the world, nor is it even the first—according to The New York Times the Slanket predates it by two years—but it is the most popular and arguably the product that made the sleeved blanket a hit with a wide swath of consumers.

But to say that it created its own market is doing it a disservice, as several news outlets have referred to its customer base as nothing less than a "cult."

These news outlets include USA Today, the San Francisco Chronicle and the aforementioned New York Times. But if it's a cult, it's a big one—in December 2009, the New Haven Register reported that about 20 million units had been sold in the 15 months since its September 2008 debut.

Spanx was founded by Sara Blakely, whose original inspiration was a condition common to many women—how to wear white pants without any uncooperative visible "blemishes," otherwise known as panty lines. She got around it by cutting the feet off of a pair of control-top pantyhose, and soon realized that a hole in the marketplace was waiting to be filled.

With that, the slimming apparel known as Spanx was born, and it became more than just a massively popular product—it became one that legions of women won't get dressed without. For identifying this niche, the company's revenue grew to $250 million, and Blakely herself achieved a net worth of $1 billion as of September 2013, according to Forbes magazine.

Trader Joe's paved the way for the organic supermarket chain, allowing it to become a mainstream entity. It launched its first private label grocery item, granola, in 1972, and made its first private label organic apple juice in 1977.

The store expanded throughout the U.S. during the 1990s, and in 2007, it eliminated transfats from its private label products, as well as artificial preservatives and genetically modified ingredients.

So while Whole Foods may get a lot of headlines as the leading environmentally conscious supermarket, Trader Joe's kicked the door down.

The Walkman was Sony's portable audio cassette player. Few people listen to cassettes anymore, so the last one rolled off of the assembly line in October 2010. But it completely changed listening habits by allowing consumers to carry music around with them—and making mass transit bearable for millions.

According to Sony, the cassette version of the Walkman sold 385 million units. And while technology changed and made it obsolete, its effect on the marketplace is undeniable—anyone listening to a portable MP3 player does so because the Walkman made portability something music listeners couldn't live without.

When FUBU CEO Daymond John found success for his urban apparel company, it wasn't just because the clothes were cool. He also knew the consumers he wanted to cater to, and he understood how to get their attention.

According to his official website, John had rapper LL Cool J wear FUBU in a promotional campaign, thereby lending it instant credibility within the hip-hop community. That credibility in turn drove sales that were strong enough to attract a distribution deal with Samsung. In an email, he said the chain of events eventually led to a contract with Macy's.

"Most designers dream of being highlighted in the windows of Macy's on 34th Street," John said. "Not just our apparel—but we physically stood in the windows of Macy's on 34th Street with crowds of people around us for about five hours one day. At that point I realized that FUBU had made it and well surpassed where I thought it could have gone."

"Shark Tank" makes its off-network debut Tuesdays on CNBC. The business-themed reality series features the sharks—tough, self-made multimillionaire and billionaire tycoons—who give budding entrepreneurs the chance to make their dreams come true and secure deals that could make them millionaires.