Two of the three finalists on NBC's "The Voice" are country acts, so the genre has good odds of producing a winner when host Carson Daly announces the results tonight. But that would only be the latest sign that country music, which brought in $1 billion in sales last year and is drawing the increasing attention of Madison Avenue, is on the move in media and marketing.

Country singers are appearing in a wide range of ads, not to mention their own TV show in ABC's "Nashville" and a prominent presence on "The Voice," where country star Blake Shelton is a coach. Even New York City, about the last place you'd expect to find fans of songs about pickup trucks and drinking beer, christened its first country radio station in 17 years in January. More than a quarter of U.S. adults now call themselves country fans, according to to Scarborough.

And its fans are willing to spend. While sales of R&B, alternative and pop dropped in 2012, country sales jumped 4.2% to 44.6 million albums out of 316 million, according to Nielsen SoundScan. It was the only category to show an increase other than rock, which edged upward just 2%. Only 13 of Billboard's top 100 songs last year were country, but four of the ten top-selling artists came from the genre: Taylor Swift, Jason Aldean, Carrie Underwood and Luke Bryan.

Adding to the appeal is that country fans are perceived as brand-loyal. While country itself appeals to multiple generations with its themes of love, family and religion, "Nashville" and "The Voice" are helping to make its case among new consumers.

"These shows are helping to widen the base of the genre and bringing more people into it," said Sheri Warnke, senior VP-marketing and communications at the Country Music Association. "Viewers think, 'I like that person, she sounds great on 'The Voice',' or, 'that winner is a country artist, so maybe I'll sample something else country.'"

With the increasing popularity comes marketer attention. Ms. Swift, Lady Antebellum and Mr. Aldean have starred in TV spots for Diet Coke, Lipton Tea and Coors Light, respectively, in the past year. Mr. Shelton appears in Walmart ads.

"Country artists have an image as someone you could walk up to at the 7-Eleven or, if they're eating at Denny's, and you could say hello to," said Robert Weiner, pop-culture librarian at Texas Tech University. "There's no elitism in their appeal. I think advertisers are aware of this. They really want to reach out to artists to promote their products, because they have an audience that maybe a rock band couldn't reach."

According to NPD's annual music study, in addition to buying more albums, country fans are also more likely than the average consumer to listen to AM/FM and online radio. And they're more likely to text message and use social networks than the general U.S. adult population, according to Scarborough research.

On "The Voice," Mr. Shelton has two of his prodigies, Danielle Bradbury and the Swon Brothers, vying for the crown. The third contestant is pop singer Michelle Chamuel.