Even the largest of retail institutions is bowing to the demands of the individual. Last July, Wal-Mart began posting consumer-generated ratings and reviews on Wal-Mart.com, saying it was the No. 1 customer-requested feature for the site. (Wal-Mart estimates that 75 percent of its 130 million weekly U.S. customers are active online.) In an earlier test of the feature, the retailer received double the number of submissions it had anticipated.

"Marketers are beginning to realize that less and less they are the sources of authority and more and more they are the sources of authenticity," says Rishad Tobaccowala, CEO of Publicis Groupe media and advertising consultancy Denuo Group. "Marketing is increasingly being outsourced to the consumer. The chief marketing officer is being replaced by the chief facilitations officer."

Tobaccowala uses one of the fiercest brand battles of the day to underscore his view: the race between Democratic presidential hopefuls Barack Obama and Hillary Clinton. Politics aside, he believes one of the reasons Obama is outperforming Clinton is that the New York senator is borrowing from marketing practices circa 1980, while Obama's strategy is rooted firmly in the present. "With Clinton, it's been top-down, command and control; with Obama, it's been grassroots facilitation," he says.

For one thing, Obama portrays an inclusive image: He uses the word "we" instead of "I." Tobaccowala believes Obama has delegated more authentically and his grassroots organization has proven deft in planning and managing the chaos of a campaign. As Clinton's organization has fumbled, her top-down style raises questions about her ability to run a country. While Obama's grassroots approach has helped him raise a lot of money, Clinton spent aggressively on a one-hour town hall meeting telecast on the Hallmark Channel this month, billed as "largest, most interactive town hall in political history." In fact, only 540,000 households saw it, and the town hall ended with Clinton being cut off in mid-sentence by a previously scheduled program, the perhaps aptly named A Season for Miracles. Obama, meanwhile, benefited from a tribute video produced by will.i.am of the Black Eyed Peas, at no cost to the candidate, inspired by Obama's "Yes, We Can" speech. It is now approaching 10 million views on YouTube.

If political candidates are having trouble with the idea of ceding some control, corporate marketers at companies like Coca-Cola and Procter & Gamble are coming to grips with it. Last year, Coke launched in a virtual world, conducting an on- and offline competition to design a "Virtual Thirst" Coke machine in Second Life. The winning design featured a series of puzzle bottles that dispense interactive experiences and Coke-branded virtual gifts. The beverage marketer worked with marketing consultancy Crayon on the initiative, and the agency's chief strategy officer, Greg Verdino, explains the new phase of Coke in Second Life this way:

"Puzzle solvers can copy the prizes they receive and gift them to their friends. Land owners can place bottles on their property, and the interactive experiences can be shared by anyone that happens to be nearby when a resident solves a puzzle. In other words, rather than taking the standard marketer approach of sinking money into an island [on Second Life] and hoping to attract residents to visit the brand, Coke is giving residents the power to distribute the Coca-Cola brand essence throughout Second Life, wherever and however they see fit."

Companies like P&G have long recognized that consumers have always helped define brands. But nearly two years ago, the company's CEO, A.G. Lafley, acknowledged the extent to which that influence has grown. His "Let Go" speech, delivered before the Association of National Advertisers, has become a corporate mantra at the Cincinnati packaged-goods giant. He said at the time: "We need to learn to begin to let go and try to stop thinking of brands from our point of view, the manufacturer's point of view, or from the industry point of view. Because in a very real sense, consumers are beginning to actually own our brands and help us define our brand equities and evolve our brand equities and participate in our brand messaging."

P&G set up Tremor, its word-of-mouth marketing unit, in 2000. The company has enlisted nearly 700,000 unpaid mothers and teens -- consumers who have greater-than-average daily contact with their peers. Tremor works for 50 clients, with about half of them outside of P&G's consumer-goods empire. Tremor used its research for one of P&G's own brands, Dawn, to help position an extension product using the detergent's new foam technology. P&G sold nearly twice as much Dawn in the market where Tremor was used.

"In almost every category and country in which we compete, if you look at every point of consumer contact -- TV, print, coupons, in-store demonstrations -- word of mouth always comes out No. 1 or 2 as the most powerful, to the degree it influences consumers about the brand," says Steve Knox, Tremor's CEO.