Brand Ambassadors are the most valuable element of your sales force. The author of "The New Influencers" explains how to get them on your team.

This fall, 42 college students will go to work on 21 campuses around the country with a simple message: Fly JetBlue. Using blogs, Facebook profiles and on-campus events, the students will spread the message that JetBlue is a cost-effective, customer-oriented airline that's fun to do business with.

The CrewBlue program -- an innovative viral marketing initiative -- makes use of incentives and word-of-mouth promotion to reach future business travelers just when they are making choices about their preferred brands.

"The power of it has been remarkable," says Tara Ryan, JetBlue's manager of national promotion. "We get much more response from student recommendations than we would from banner ads."

In the hyper-competitive market for air travel, budget-busting advertising campaigns are a luxury few companies can afford. That's one reason JetBlue's experiment is drawing so much attention. Although the airline hasn't tried to quantify the results of the campaign, company research has found that 81 percent of JetBlue flyers recommend the airline to someone else.

It's no secret that customers are the most powerful marketing vehicle a business or organization can have, and a new breed of marketing program that enlists the power of "brand advocates" is showing early success.

People instinctively trust the opinion of a customer -- even someone they've never met -- over a marketer or even a published review. In a 2005 survey by research firm GfK NOP, 92 percent of U.S. consumers cited word of mouth as one of the best sources of information about products and services.

The internet -- and the new class of so-called social media sites and functionalities in particular -- offers marketers some powerful new ways to lasso and engage brand advocates, turning them into de facto extensions of your sales force. Let's look at what's working.

Next: What's a brand advocate?