Deloitte’s Consumer Products group found 62 percent of people read consumer -written product reviews online. Out of those who read product reviews online 82 percent said their purchase decisions had been influenced by reviews causing them to buy a different product than originally intended or causing them to stay with their original choice.

Sixty-eight percent of Gen Y rely online reviews the highest of any age category, while 42 percent of those age 75 and over use online reviews, the lowest in any age category. The reach of consumer reviews is also offline with 69 percent of consumers who read reviews sharing them with friends, family or people they work with.

"This increasing market transparency can adversely impact the margins, market share and brand equity of consumer products companies," said Pat Conroy, vice-chairman and US consumer products group leader at Deloitte & Touche USA LLP.

"In the past, clever marketers and advertisers shaped brands, but now consumers are increasingly empowered, everyone has a voice, and information and opinions are instantly dispersed."

Conroy said that consumer product companies should learn to use reviews to their advantage or else deal with the outcome.

"As knowledge proliferates, there is a tendency for products to commoditize," said Conroy. "In order to successfully compete, it’s imperative for consumer brands to build and maintain their images, create differentiation, and enhance loyalty."

"For example, consumer product companies with exemplary supply chains can achieve differentiation by making their processes more transparent. Embracing higher-than-required quality and safety standards can reassure customers and built trust. And co-opting customers to create value with the company can create not only loyal customers, but also brand emissaries."

Over eight in ten respondents in the Deloitte study who read consumer reviews said that they had impacted their buying intentions. They were either more determined to make a purchase or had second thoughts and made a different purchase.

Pat Conroy, vice chairman and US consumer products group leader at Deloitte Touche USA, said, "This increasing market transparency can adversely impact the margins, market share and brand equity of consumer products companies."

"Consumers are increasingly empowered, everyone has a voice, and information and opinions are instantly dispersed," he said. "Consumer product companies need to determine how best to capitalize on this new landscape."

In a separate study conducted by Deloitte in August with Sterling Commerce they found that 42 percent of U.S. online shoppers believed that having consumer reviews on Web sites increased trust in the sites.

Only 32 percent of U.S. ecommerce sites allow consumers to post reviews, according to an Internet Retailer Vovici study, the rest of the sites that do not allow consumer reviews are missing out on the opportunity to build site trust.

More than eight in 10 UK consumers researched online before booking a hotel and 62 percent did the same with restaurants.

Seventy-seven percent of UK hotels and 80 percent of restaurants said the growth in consumer-generated content is a business opportunity.

Kathryn Pretzel Shiels of American Express said, "The industry is clearly taking steps to better understand this channel. In fact, 67% of UK hotels and 77% of UK restaurants say they actively monitor content posted on independent review sites."

The study also asked hotel and restaurant operators about online marketing and found that 57 percent of hotels and half of restaurants used affiliate marketing. Seven out of 10 hotels used direct e-mail and just 17 percent of restaurants did.