"When we launched we were offering something unique," continues Jarvis. "There was nothing else like Cravendale and consumers like choice. It is not an easy battle to get consumers to change their perceptions and choose a different product. But we've got a fantastic brand built on a product truth."

According to Dolak, challenger brands must promise something of value, offer something unique and then deliver on the promise. Certainly, the product must offer a real benefit (better taste, meets a need, solves a problem). "If consumers perceive there is a low risk to trying something new, they will do it once. But if the new product does not live up to its promise the consumer is more than likely to switch back," he says.

Cravendale focuses on its fresh taste. "Our target audience is mums with kids," says Jarvis. "Children are the greatest consumers of milk, so to get the best returns we target this audience. Cravendale has exactly the same nutritional benefits as other milk, so we couldn't market it on nutritional benefits. Our message is all about its fresher taste—so good the cows want it back! This is very motivating to mums. By providing a fresher tasting product they are reassured that they will still get it down their children." Jarvis also concedes that children, who are increasingly "brand-savvy," also like the branded product, although she says Arla has no intention of using "pester power" to further boost sales.

Karan Bilimoria, founder of Cobra beer in the UK, certainly knew what he wanted his product to offer: a less gassy beer that had all the taste of ale, but was as refreshing as lager. In its early days, when Cobra was building up its distribution through Indian restaurants, the beer focused on what it had to offer: its distinct product characteristics. Even when the brand went mass market in 1997 with its "Curryholic Dave" series of advertisement, the emphasis was still on its Indian heritage and its less gassy nature. Cobra quickly became the "curryhouse beer."

It is important to find a niche, says Dolak, and he argues that the days of mass marketing are over. "It is healthy to see any market as a collection of niches," he says. "I feel that mass market appeal to hundreds of millions of consumers is over. Consumers want products they feel are customized to just the way they want it. Focusing on a niche, at least at first, is the preferred way to go. You can find an under-served segment and specifically address its unmet needs."

Edwin Colyer is a science and technology writer based in Manchester, UK.