(FORTUNE Small Business) – The problem with working for an outfit such as Blue Cross Blue Shield of Michigan is that everyone thinks you can answer medical questions. The situation becomes even more vexing when your 69-year-old father turns to you and says, "I need quadruple bypass surgery. Where do I go?" That's the challenge Rick Morrone faced last Thanksgiving. "I'm a sales guy, not a doctor," says Morrone, who is director of national sales and marketing for the company. He turned to friends and family for fast referrals, but instead received conflicting and confusing advice. That's when he remembered Subimo.

A few months earlier the founders of Subimo--a five-year-old, 25-employee company from Chicago--had traveled to Morrone's office in Detroit to pitch their service: an easy-to-navigate database of health information designed to help patients find and compare doctors and hospitals as easily as they might choose restaurants from a guidebook. Morrone had thought little of the company since the presentation, but he'd held on to the web address of a demonstration site. On a lark he logged on. An hour later, Morrone learned that the top-rated cardiac-care hospital in Michigan happened to be a ten-minute drive from his dad's Dearborn home. He also found a list of straightforward questions to ask his father's doctors before and after the operation. By the end of January, Morrone's dad was on the mend, and Subimo had a new client: Blue Cross Blue Shield of Michigan.

The thousands of businesses that signed up for some form of consumer-driven health care last year may have helped make CDH the hottest medical acronym since HMO, but they've tended to overlook one major obstacle. Although the plans aim to encourage smarter health-care spending by placing more responsibility on the employee--in the form of higher deductibles and personal accounts--they tend not to provide information to help patients make those decisions. A June survey by benefits-consulting firm Towers Perrin found that 85% of insured workers say they lack the information or tools needed to make good health-care decisions. "You can still find more information on buying a used car online than you can about a physician or hospital," says Ann Mond Johnson, Subimo's president.

That insight led Johnson to form Subimo--a loose acronym for "So you'll be informed more often"--in 2000. Subimo's technicians compile reams of disparate data from private research firms and public sources like state health-care agencies. They then embellish that information with a simple navigation tool and sell the finished product to health insurance firms as well as to large and small employers. Today health plan providers, including Harvard Pilgrim and Oxford, offer Subimo's technology to their members. Subimo reaches consumers in every state. And this fall, Johnson and her team are reaching out directly to individual customers with the launch of myhealthcareadvisor.com, a website that charges $12 for six months' access. "For our money they are the best database and decision tool out there," says Subimo client Michael Parkinson, chief health and medical officer of Lumenos, based in Alexandria, Va., which provides consumer-driven health plans in all 50 states.

Johnson, 49, spent nearly a year working as a coat-check attendant before earning dual master's degrees in business and public health from the University of Minnesota. She landed a job in business development with Sachs Group, a medical software and information company, but left when it was bought in 1999. "They weren't interested in providing consumers health information in the way I envisioned," says Johnson. "It was an opportunity to do something on our own." Unable to raise outside capital, Johnson and her three co-founders--fellow Sachs dropouts--financed the company with their personal credit cards and got about $900,000 from friends and family.

So it is perhaps not surprising to hear of Subimo's frugal spending philosophy: "Kiss every penny you spend and tell it to come home soon." Instead of headquarters, Johnson rents offices and a conference room by the hour on the 21st floor of a downtown Chicago high-rise. Subimo shares its space with 67 other companies. Most employees--including the Los Angeles--based VP of marketing--work from home, and meetings are usually held via teleconference or instant message.

So far the company's modest approach has resulted in only modest results: Although Subimo reaches 60 million customers, last year's revenues barely hit $10 million. Thanks to its frugality, the company turned a profit, but considering that Forrester Research, based in Cambridge, Mass., calculates consumer-driven health care to be a $16 billion industry, Subimo's failure to reap more revenues may seem an underachievment. But Johnson argues that her corner of the billion-dollar consumer-driven health market is still young, and she expects revenues to rise as she convinces more customers of her service's value. Five years ago, Johnson adds, her sales pitches received blank, uncomprehending stares. Now "we're profitable and we're growing steadily. I'm fine with that."

But in the coming months Subimo will face competitors less likely to be satisfied with such results. In March, WebMD, a $1-billion-a-year online company that provides everything from billing services to medical research data, spent $31 million to buy HealthShare Technology, a web company with a hospital-comparison tool similar to Subimo's. WebMD intends to use the purchase as the backbone for WebMD Health, a consumer site that will compete with myhealthcareadvisor.com and may go public next year.

Then there's Steve Case's Revolution. Founded in April, the new company dabbles in everything from holistic resorts to a new, health-focused cable channel to an online endeavor that Case says will "put consumers back at the center of the system by giving them more choice, control, and convenience--while building the first comprehensive, consumer-driven health-care company." Case, the founder of AOL (owned by the parent of FSB's publisher), is fronting $500 million of his money and has won additional investments from celebrity CEOs and from Secretary of State--turned--venture capitalist Colin Powell.

Johnson shrugs off the threats with trademark understatement: "Do you really think Steve Case and Colin Powell can fix health care? Whatever." But Johnson will need more than a dismissive attitude, says Forrester analyst Katy Henrickson. "This is an increasingly crowded niche," she says. "You can't ignore larger and better-funded rivals." Johnson insists she is not ignoring them. While her rival is busy ramping up or filing reams of documents with the SEC, Subimo is acquiring databases so it can provide more complete information on doctors and hospitals.

Another of Subimo's competitive advantages may be its modesty. Lumenos's Parkinson says he chose Johnson's company over WebMD in part because she didn't insist on placing an obtrusive logo on his company's website. (The only indication of Subimo's presence: a tiny footnote that reads "Powered by Subimo.") "We didn't want our members to ferret through a byzantine maze of disarticulated brands," he says.

For Rick Morrone of Blue Cross Blue Shield of Michigan, Subimo was a no-brainer to use or choose. "When you or someone you love is slated for surgery, the last thing you want to do is struggle to find information," he says. Based on his experience, he's gladly recommending Subimo to other Blue Cross plans around the country. If Johnson's going to beat back her rivals, she'll need a few more referrals like that.