Few entrepreneurs break more rules than Ben Cohen and Jerry Greenfield of Ben & Jerry's Homemade Inc. But lately they've been learning there are some rules you just can't ignore. The lesson involved their idea for a new product, the Peace Pop, an ice-cream bar on a stick that would compete in supermarket freezers against the likes of Dove Bars and Jell-O Pudding Pops. Aside from providing much needed diversification, the Peace Pop would be used to build awareness and raise funds for a movement the Vermont ice-cream mavens have cofounded called 1% for Peace. They rushed the product into stores about a year ago -- and then watched it languish.

For openers, there were quality problems. "We should have let the pop evolve to its most delicious state before introducing it," says Greenfield. Meanwhile, the company's low-budget, low-key, grassroots marketing strategy turned out to be no match for the marketing blitzes of competitors. After six months, sales of the Peace Pop were running at 50% of projections.

In studying the dismal returns, however, Ben & Jerry's marketing people noticed one bright spot: the Peace Pop was doing well at local delis. They concluded that the pop was an impulse buy rather than a product Mom was willing to heap into her cart at a hefty price. Today, after months of fine-tuning, 70% of Peace Pops end up in convenience stores, and sales have increased 60%.

And the lesson? "We learned that a product doesn't sell just because you're trying to do good in the world," says Greenfield. "You still have to have a healthy distribution, a good marketing strategy, and price the product properly."

-- Elizabeth Conlin