By now, you'd have to be living in a cave to not know about Lindsey Vonn. The golden girl of the Winter Olympics, a Minnesota native, got the big pre-Games buildup and delivered a gold medal in the downhill, Alpine skiing's signature event.

Good for her. Yet Vonn didn't need a gold medal to validate her career. She was already a two-time World Cup overall champion — meaning she finished as the world's best skier over a long, grueling season.

But to the average American, athletes in Olympic sports are invisible unless they win a medal, preferably a gold. After years of success at the highest level of sport, an athlete's post-Olympic marketing potential — and millions of dollars in lifetime income — can be determined by the smallest margin of victory or defeat on a single day.

Do you remember Dorothy Hamill? If you're a Baby Boomer, of course you do. She was a world champion figure skater and won Olympic gold in 1976. Hamill's bobbed hairstyle was widely copied and she still commands upwards of $25,000 for speaking engagements — more than 30 years after her Olympic win.

Linda who?
But do you remember Linda Fratianne? A contemporary of Hamill's, she had arguably a better career, winning the world figure skating championship twice to Hamill's once. But at her only Olympics, 1980 in Lake Placid, she finished second. Nobody's paying Linda Fratianne $25,000 to speak at their annual convention.

Or Rosalynn Sumners, world figure skating champion in 1983 and Olympic silver medalist in 1984. Or Minnetonka native Jill Trenary, world champion in 1990 but fourth-place finisher — out of the medals — at the 1988 Olympics.

The same dynamic is at work in the Summer Games. How many of you have heard of Allyson Felix? She's one of the greatest sprinters in history, winning the 200 meter dash at the track and field world championships in 2005, 2007 and 2009. No other woman has won the event three times.

But she couldn't duplicate the feat at the Olympics, taking silver in the 200 meters in 2004 and 2008 (although she did win gold as part of a relay team).

Yet people still remember "Flo-Jo:" Florence Griffith-Joyner, who never won a gold medal at the world championships but blew away the sprinting field in the 1988 Seoul Olympics.

It helps that Flo-Jo was a flamboyant, memorable personality who competed in self-designed uniforms and extravagantly decorated fingernails. Look at the unassuming American skier Phil Mahre, who won three overall World Cup titles as well as Olympic gold, but isn't much remembered outside of his sport.

Meanwhile, the Italian Alberto Tomba — aka "La Bomba" — had similar success on the slopes, but parlayed his larger-than-life persona into millions of dollars in endorsements.

The same athletes compete against each other in the same events every year, but somehow the competition only matters to America every fourth year. It's as if the Twins were considered failures because their World Series titles came in 1987 and 1991 instead of 1988 and 1992.

The marketing lesson of the Olympics is: gold leads to gold.