(FORTUNE Magazine) – Most new-product manufacturers would kill for the instant name-brand recognition of Miller Brewing, General Motors, or Coca-Cola. But these companies are finding that their greatest asset can sometimes prove a liability. The hottest brand strategy for winning new markets is to leave your corporate identity at home. Miller is trying to tap into the trendy microbrewery market with its new Icehouse line, which looks, in ads, as if it's made by a scrappy little company. Indeed, the beer's label credits the quaint-sounding Plank Road Brewery -- Miller's original name. Says President John Bowlin: "We thought we could evoke the spirit of a small brewery like Sam Adams." Some well-known names just don't pay anymore. Almost every car buyer, for example, knows the name Oldsmobile -- but many associate it with clunky mid- range cars. The GM division once tried to change its image with the "Not your father's Oldsmobile" ad campaign. But now they're going even further, marketing their 1995 luxury sedan, the Aurora, with virtually no reference to Olds. The strategy is designed to win younger luxury buyers, who have never taken to Oldsmobile. Big isn't even better for Coke, once named the World's Best Brand by this magazine. Neither of its new products, OK Cola and Fruitopia, features the Coke swirl. OK is aimed at the 12-to-29 slackers, while Fruitopia is being sold to the same New Agers who drink Snapple -- neither group a market that vibrates to the tune of Coca-Cola, the multinational conglomerate. One fallout of the trend is that it's becoming increasingly difficult to tell which small brands are for real and which are faux front operations. That lemonade stand at the corner? Check again. It might be a division of PepsiCo.