JEFFREY KAYE: On a street corner in South Central Los Angeles, rap music promoters hand out CD's, posters, and stickers. Known as street teams, they're hired by record companies to promote hip-hop music directly to customers.

T. BROWN, Promoter: It's more awareness. We've just got to let everybody know. It's like we have big mouths.

JEFFREY KAYE: This guerrilla marketing strategy was a response to the initial reluctance of radio stations to play the music. Street teams, together with the successful promotion of music videos, have transformed hip-hop. Once a marginalized, black urban music form, hip-hop now is not only mainstream Americana, it's a thriving, billion-dollar-a-year industry. Last year, hip-hop records outsold country music, and the growth of hip-hop sales surpassed rock.

DAMON DASH, CEO, Roc-A-Fella Records: Where rock and roll has decreased, hip-hop has increased.

JEFFREY KAYE: Damon Dash is CEO of Roc-A-Fella records. The label is owned by rap star Jay-Z, whose current album has topped pop charts for the past 15 weeks. Dash says hip-hop is popular because it is more than just a music genre.

DAMON DASH: I think the reason why is just because hip-hop depicts a lifestyle, you know, just reports what's going on. And people can understand the struggle through the music. It's not just the music.

JEFFREY KAYE: The term "hip-hop" is used interchangeably with rap to describe the rhyming music. But hip-hop also more generally describes a culture and fashion beyond the music. Hip-hop reflects an urban aesthetic, a style and attitude seen by millions on rap videos. Its appeal cuts across class and racial lines, and is embraced by suburban as well as urban consumers.

GIRL: I like the style, the look, the music.

GIRL: It's definitely more entertaining. Country makes me sick.

JEFFREY KAYE: Seventy percent of all rap consumers are white, according to Soundscan, which tracks album sales. Nazareth Nirza, a Filipino-American, says he identified with the music's outsider status.

NAZARETH NIRZA: I didn't grow up in the ghetto, I grew up in a suburban area. But, you know, I was able to relate to it in terms of, like, you know, not being your traditional Asian kid, going to school and stuff, you know.

JEFFREY KAYE: Such crossover appeal has turned record label Def Jam, the producer of top rap artists like DMX, into one of the hottest music companies in the business. Motti Shulman is an executive with Def Jam.

MOTTI SHULMAN, Definition Jam Recordings: We've definitely tripled our sales, more than tripled our sales in the last year.

JEFFREY KAYE: To what?

MOTTI SHULMAN: I think it's somewhere around $190 million, more than doubled our best year ever in history. It's no longer just an inner city thing. It's white kids from the valley here, or, you know, the suburbs, definitely, wearing the clothes, living the life, listening to the music.

JEFFREY KAYE: Rap was born in the South Bronx more than 20 years ago. Acts such as Grandmaster Flash and The Furious Five depicted a stark view of black urban life. Rap is varied and evolving, but the gritty, sometimes vulgar lyrics are often about life on the streets-- poverty, drugs, sex, and violence. The form, as well as the content of rap, suggests rawness. The staccato rhyming of rap artists is often performed to the accompaniment of excerpts from vinyl records. Ralph M. of the group Funkdoobiest calls himself a "turntable-ist," mixing and using portions of records in a technique known as sampling.

RALPH M., Funkdoobiest: You can actually take a chord from a record now and sample it, and play that chord.

JEFFREY KAYE: Could you give me an example?

RALPH M.: Depending on how good your ear is, you know?

JEFFREY KAYE: Could you give me an example?

RALPH M.: Um, yeah. Well, actually -- (Playing sample) this is like a vocal, you know?

JEFFREY KAYE: Right.

RALPH M: I could incorporate this with a drum track here -- that's a kick.

JEFFREY KAYE: So what do you use the two record players for, the two turntables?

RALPH M.: Well, I use that a lot of times because you can keep the music continuous, and the other thing, too, is when you get into what is known as, you know, cutting and scratching, you can actually repeat the records. (Playing sample) Right to the top.

JEFFREY KAYE: And you're taking, borrowing, stealing, sampling from everything?

RALPH M.: Well, creatively borrowing, let's say that.

JEFFREY KAYE: Creatively borrowing, okay. Let's say that.

ICE CUBE, Rapper/Producer: Gangsters and drugs make my world tour. No hesitation I can run a nation from incarceration...

JEFFREY KAYE: In the late 80's and mid-90's, rappers like Ice Cube came in for criticism for so-called gangsta rap. Critics said rappers advocated hatred, and glorified violence and drugs. But Ice Cube defended his music, saying it was an artistic portrayal of reality.

ICE CUBE: The video is entertainment, you know what I mean? The video is the same thing Stallone or Schwarzenegger does for a living. "Gansta Makes the World Go Round" it just - really just showing what we've got, you know. Like I said, as a society in 1997 -- we're mirrors of this society. We're not - you know, we're not -- we've come from this society.

JEFFREY KAYE: The worlds of gangsters and rappers collided in 1997 with the slayings of Tupac Shakur and notorious B.I.G.. But the murders of the rap stars did not taint the popular appeal of hip-hop. University of Southern California Professor Todd Boyd, author of a book about urban culture, says rap's outlaw reputation is one of the reasons for its popularity.

TODD BOYD, University of Southern California: I think we've always had some fascination with those people who openly flaunt the rules of society, be they Jesse James or Tupac Shakur.

JEFFREY KAYE: For that reason, says Boyd, rap reaches way beyond those who can personally identify with the music.

TODD BOYD: The fact that the lyrics don't represent their life or reflect their life is secondary to the fact that this is good theater, this is good cinema, this is good music. And people feel that -- that sense of authenticity comes through, and linking that with this larger sense of the visual, I think, makes this a very spectacular form of popular culture.

JEFFREY KAYE: Hip-hop is universal, according to disc jockey Son Doobie, a Puerto Rican. He hosts a show on one of LA's most popular urban music stations, and has toured the world as a hip-hop performer.

SON DOOBIE, Funkdoobiest: Now it's done globally, you know what I'm saying? There's hip-hop in Japan, there's hip-hop in Australia, in Europe now, you know what I'm saying? It's a spectrum with just everybody, you know, a diverse culture that everybody just practices and subscribes to.

JEFFREY KAYE: At LA's House of Blues, where Son Doobie performs with partner Ralph M., that diversity is apparent in the audience. There, Latinos, African-Americans, and whites rub shoulders to Funkdoobiest's rhymes. Hip-hop has mass appeal because it is theatrical, yet rooted in the reality of the streets, according to Todd Boyd. Popular albums carry parental advisory stickers because of explicit lyrics.

TODD BOYD: It never compromised in order to make itself popular. It maintained its edge, and so it doesn't matter if something is controversial, if something's threatening, the more of an edge you have probably the better chance you're going to have at being successful.

JEFFREY KAYE: On trendy Melrose avenue in Los Angeles, it's apparent how commercial hip-hop culture, with its baggy fashions, has become. Against a backdrop of graffiti art and break dance videos, brand-conscious customers snap up oversized T-shirts and sportswear. Hip-hop music is used to sell fashion, soda pop, and movies. In last year's "Bulworth," Warren Beatty's Senator Bulworth expressed himself in rap.

WARREN BEATTY: As long as you pay I'm going to do it all your way. Yes, money talks and the people walk.

JEFFREY KAYE: And in the entrepreneurial hip-hop world, many rap artists are making big money from their art. Last year, rappers Master P. and Puff Daddy appeared on Forbes Magazine's list of top 40 entertainers. They each earned more than $50 million by recording on their own labels, as well as putting out clothing lines. Jay-Z's clothing label, roc-a-wear, will be out in the fall, according to partner Damon Dash.

DAMON DASH: I mean, why shouldn't we capitalize, when everyone else is capitalizing off our lifestyle, why shouldn't we? You know, we just got to learn the business, make it lucrative to us, and just, you know, go about it right.

TODD BOYD: What better way to expand your popularity, as well as, you know, make more capital, than by saying, you know, "not only can you listen to my music and buy my CD's, but you can also, you know, dress in the same style as well"?

JEFFREY KAYE: So you've got culture and commerce each feeding off the other.

TODD BOYD: Yes. Yes. Yes. And this is one of the first times in history that African-Americans have been able to exert some sense of personal agency, some sense of control over culture and commerce at the same time.

JEFFREY KAYE: Tonight, with hip-hop star Lauryn Hill up for ten Grammy Awards, hip-hop will be center stage. Hill's solo debut record has been nominated for album of the year. Its songs range from rap to rhythm and blues, reflecting a variety and complexity that is earning hip-hop growing commercial success.