Based on Vitrue's "Social Media Index," the list ranks brands by activity on social media Web sites. Ford comes out No. 1, followed by sibling brand Lincoln. Ford has been focusing heavily in social media this year to promote its 2011 Fiesta subcompact.

Other brands in the list were GM in third place, followed by Honda, BMW, Mercedes, and Dodge. At the bottom were Kia, Subaru, Chrysler, Volvo and Chevrolet at last place.

The firm, which listed Apple's iPhone as the most digitally discussed brand in 2008, this year measured first-quarter auto brand chatter on sites like Facebook, MySpace, Twitter, and even photo and video sharing sites, and the blogosphere.

Vitrue cites comScore numbers suggesting that Facebook reaches an audience of 200 million users averaging 169 minutes a month. More than 50% of Facebook users and 44% of MySpace users in the U.S. were over 35 years old, also according to comScore estimates.

Vitrue CEO Reggie Bradford says the firm looks at share of voice in social media. "Probably about six months ago, we began getting feedback and requests from marketers on how to get going in the space and understand the market," he tells Marketing Daily.

The index does not discriminate between positive and negative sentiment. And Bradford says that matters less than the fact that people are talking. "It's really a measure of buzz, and the more people are talking about a brand, the better."

The measures are not necessarily limited to the U.S. since the company looked at English-language sites, not country-specific media. "It's a combination of ubiquity social interaction and a brand's ability to capitalize on buzz, build conversations and get consumers involved in talking about brands," says Bradford.

As part of its plan to promote Fiesta, Ford tapped 100 social-media mavens with 1,000 or more fans on sites like Facebook, Twitter and YouTube to document their experiences with the car. They will drive the car for six months, and it is expected, generate a kind of social media avalanche about the vehicle. Ford says the "agents" are also meant to talk to Ford about the car's plus and minuses.

Bradford says that the size of the company involved and market exposure did not determine ranking. "You see some of the prestige brands, like BMW and Ferrari [No. 8 on the list of 20 auto brands] well up on the list.

"We think of this as the 21st-century call center; it's ongoing, and you have to be vigilant and committed to becoming social as a brand if you are going to get into it; you can't get in there half-baked, do something and run."

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