In 2009, after nearly a decade on the market, the Orabrush tongue cleaner had sold fewer than 100 units, at $5 apiece. Business – crawling at the pace of one order every 36 days – wasn't exactly booming.

The product's inventor, Robert Wagstaff, who is based in Provo, Utah, had taken the Orabrush to retailers such as Walmart and CVS to see if they'd want to sell it. They didn't. So he spent $50,000 on marketing the product with an infomercial. That didn't work. He even tried to sell the patent for his invention – a tongue brush with surgical scrub bristles and a plastic scraper – to Oral B.  The answer was no.

In a last ditch effort, Wagstaff, who goes by Dr. Bob, brought the Orabrush to a marketing class at Brigham Young University's graduate school, which offers companies the chance to let students perform a case study for them for about $1,500. The students studying the case found that 92 percent of the retail market simply would not buy the product.

Jeffrey Harmon, then a 26-year-old student, raised his hand. It was Harmon's final class of his last semester of his final year of college. What about the other 8 percent, he wanted to know.  "I just expressed that I felt like you have better chances online than you do against the retailers," says Harmon, who himself had used and enjoyed a tongue scraper in the past. "You have the visual, the instant gratification of seeing the stuff come off, plus the knowledge that you're getting rid of your bad breath."

He approached Dr. Bob at the end of the class.

"I'm really interested in your product," he told the inventor. "I think I can sell it."

Thus began a partnership that would take the Orabrush from a lame duck to a world-recognized Internet phenomenon.

Until October 2009, Harmon worked full-time at another job while spending his nights exploring new ways of selling the obscure tongue brush. "I was trying to figure out how to sell Orabrush using Facebook," he recalls, "so I posted a video on how to tell if you had bad breath."

It was based on a generic video he found on YouTube, which he had gotten permission to use from its creators. The simplicity worked.  "It boosted our conversion rates by three times," Harmon says. "If people know how to tell if they have bad breath, they're a lot more likely to buy the product."

So, he thought, "What if we had a video that taught people how to tell if they had bad breath and in the same video taught them about Orabrush … and it was funny?"

At this point, Austin Craig, a coworker of Harmon's, entered the picture. After watching Craig become embroiled in a heated discussion that made his coworkers laugh, something in Harmon clicked. "Can you do that, but about bad breath?" Harmon asked him. Craig said sure.

Along with Jeff's brother Neal, who is now the company's chief operating officer, the team produced their first YouTube video for less than $500. They shot it in a pool room. (If you listening closely, pool balls can be heard cracking in the background.)

The first video was an "edutainment ad," according to Harmon, because it aimed to, well, both educate and entertain. It showed viewers how to use a spoon to determine if they had bad breath. "When you ask people how to tell if you have bad breath," says Harmon, "almost no one knows. They will say things like 'blow on your hand' or 'blow on a friend'... very few people know to lick a spoon, let it dry, and then smell it." 

Though the marketing team didn't have the type of budget that could instantly place their video in front of thousands of viewers, Harmon continued to invest wisely in the YouTube campaign. "We started out on YouTube with a $40 a day spend. Then, as soon as I could get $45 back, we upped it," he says. "And then I just dumped all of our profits back into the campaign and it just grew and grew and grew."

In five weeks, Orabrush sold out 10,000 units. The company ordered more inventory and sold out again. More succinctly put: "It exploded," Harmon says.

Since it launched a year ago, the Orabrush YouTube channel has garnered more than 24 million views and 250,000 fans on Facebook. Online alone, the company has passed $1 million in sales, and demand shows no sign of slowing down. According to Dr. Bob, he has had requests for distribution from  retailers and distributors in mroe than 40 countries. Boots, the British pharmacy giant, now carries the Orabrush, as do as stores in Japan, Canada, and soon, Australia.

According to Harmon, the secret to the campaign's success is simple: People don't really know what causes bad breath, even though studies show that 90 percent of bad breath comes from the tongue. So it stands to reason, then, that the number of searches for tongue brushes on Google and Yahoo are low.

"One of the great things about Orabrush, is that we know we're expanding the category," says Harmon, who now serves as Orabrush's chief marketing officer. "We did a survey and found that 8 out of 10 people who are buying Orabrush have never used a tongue cleaner before. Almost all of the users are new."

Out of the online sales that Orabrush reports, 60 percent were to domestic consumers and 40 percent of buyers were international, according to Jeff Davis, a former executive at Procter & Gamble who now serves as Orabrush's CEO. Of that 40 percent, he says, the Orabrush was sold to customers in 113 different countries. After working in five different countries for several of Procter & Gamble's brands, Davis notes that Orabrush's story is "really, really unique."

One viral-marketing take-away that Harmon and his team found is that, to gain a loyal following on YouTube, one should create a steady stream of content; it's not enough to be a one-hit wonder. "Everyone is on a rampage to figure out how to make their viral video. I've had a lot of people e-mail me asking how to create a viral video for YouTube," Harmon says. But he says the approach needs to be more thoughtful than that. "People don't want to hear bad breath jokes every single week," he explains. "They'll get old eventually."

These days, Orabrush's weekly YouTube videos aren't just instructional. The latest episodes are part of a series called "Diaries of a Dirty Tongue," and feature a foul-mouthed giant organ. Morgan, the tongue, symbolizes bad breath – rude, obnoxious, something you just don't want to be around. He never directly mentions or promotes the tongue brush itself, but the message is clear enough: Clean up that foul mouth of yours.

It's an indelicate message but, as the orders pouring into Orabrush make plain, it's another brilliant resonant campaign courtesy of an MBA student with a knack for viral marketing.