"You have to look at it as woven into the overall fabric of the program and not as something that stands on its own," she said on a panel at the 4As media conference.

As an example, Fay pointed to a McDonald's push last year--mentioned first by a MySpace executive--celebrating the 40th anniversary of the Big Mac. The fast-food company wanted to capitalize on nostalgia for the burger's memorable jingle to improve sales. So it used social-networking site MySpace as well as traditional media for the campaign.

McDonald's ran a contest on MySpace challenging people to come up with their own version of the famed: "Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame-seed bun." TV and print ads--as well as some online ones--promoted the contest. The winner earned a role in a Big Mac TV spot.

With social media, advertisers aim to develop grassroots brand ambassadors--a tactic that can carry the term "influencer marketing."

Heidi Browning, senior vice president, insight and planning at MySpace, said 1 million people "interacted" with the Big Mac brand as the contest was taking place. Browning, who joined Fay on the panel, said Carat is a bellwether in the social-media marketing arena. "We always look to Sarah's team as being the leader in best practices," she said.

Social-media marketing frequently involves setting up a MySpace, Facebook or Twitter presence that can become a forum for consumers to convey passion for brands. That version of pull rather than push marketing can have a viral effect.

Fay, however, said that it is critical to avoid letting a MySpace page or presence on another site grow stale. Brand advocates are likely to lose passion if the site lacks vitality. "Keep it refreshed," Fay said.

She added that it is crucial to pay attention to what consumers are saying and react accordingly, perhaps tinkering with the page's dynamic. Josh Bernoff, vice president and principal analyst at Forrester Research, emphasized Fay's point, saying that marketers must tune in and fine-tune. Monitor the commentary and adjust the marketing messages accordingly, he said.

Bernoff served as the panel moderator and told the audience: "Your brand advocates are out there, and [so is] the information about how they feel about [your brand]. "If you listen in a qualitative way, you're probably going to end up a lot smarter as you enter this space."

One advertiser tuned in this week and didn't like what it saw, prompting a swift reaction. Marketers for the candy Skittles had to yank down a Twitter presence, since troublemakers started typing in profanities that made it to the Skittles Web site. In looking for brand ambassadors, Skittles found the opposite.

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