So, how do you make WOM marketing work for your brand? Sernovitz advises that you stick to his 5 Ts:

Talkers. Identify the people who will do the talking for you. And remember, these people aren't always going to be your customers. They might be the mothers-in-law or the friends of the customer. Either way, they're going to be the ones starting the conversation about your product.

Topic. Unlike slogans and marketing messages, which no Joe Six-Pack is going use in real-world conversation, develop a broad topic your talkers can talk about. Lenovo's talkers could focus on how easy the company's tools made on-the-go communication; Fiskars customers can talk about how the company's products help with their favorite hobby or how much they like the community spearheaded by Fiskars.

Tools. Make sure the tools you select for spreading your message are ones that are likely to be used by your talkers. If your target audience is middle-aged bowlers, then Facebook and MySpace might not be the best places to start.

Taking part. Sernovitz warns that this T tends to scare marketers the most because it's the least familiar. "Most marketing departments are set up for one-way, outbound marketing," he says. But to get WOM to work, brands must participate in open-ended conversations on blogs and social networking sites. As the conversation grows, says Sernovitz, marketers must be willing to devote more resources to keeping it going.

Tracking. Marketers should also remember to build trackability into their campaigns. Secret discount codes in emails are extremely trackable, Sernovitz says. He adds that pretty much any action step that requires clicking or notifying others of an opportunity at the end of a WOM discussion will lead to the kinds of numbers marketers love.

Matt Moog, founder and CEO of Viewpoints Network, whose consumer review site is a WOM-based business, says it's important to keep campaigns simple and targeted. If a campaign "is barely related to your brand and doesn't do anything to reflect the product that you sell, that's not practical and sustainable," he says. 

A recent example of a somewhat misguided WOM campaign comes via Ivanka Trump. Trump teamed up with Healthy Choice to promote its Fresh Mixers line, which essentially consists of MREs that can last up to a year in your desk drawer. Because when you think of eating a quick lunch at your desk, you think of... a Trump?

The campaign involves in-person appearances with Trump along with a blog she supposedly maintains at blog.alunchtrade.com. Though the campaign uses tools typical of WOM marketing, "It isn't really word of mouth," says Sernovitz. "Just because it's a blog doesn't mean it's word of mouth." Sernovitz suggests that Healthy Choice would have made a better marketing investment by focusing more on its message boards. He points out that thousands of visitors have posted on Healthy Choice's message boards, but that the company didn't get involved in those conversations. "They got the theory right, but the taking part was missing," says Sernovitz. "It just sort of faded away."

Leah Messinger is a freelance writer.