Fort Minor - "Where'd You Go" Video (Uncensored)

Fort Minor's "Where'd You Go" video, featuring interviews with families of US troops currently in Iraq, and filmed in the homes of those families.

Fort Minor's 'Where'd You Go' Is a Rap Hit by a Rocker Fort Minor, a hip-hop side project of Mike Shinoda (center) from the rap-rock band Linkin Park.

If you were watching MTV's countdown show "TRL" last week, you may have noticed a hip-hop video near the top of the heap. Over the last few weeks "Where'd You Go" has become one of the channel's most popular clips: it's a melancholy breakup song, with the rapper adopting the perspective of his fed-up girlfriend.

It has a quiet chorus (from a female collaborator) and rhymes full of resentment: "I feel like an idiot working my day/ Around a call, but when I pick up I don't have much to say." The song has been moving up the radio airplay charts too; it may have enough momentum to reach the Top 10.

Yet Fort Minor "Where'd You Go" has scarcely made an impression in the hip-hop world. The rapper is Mike Shinoda from the mega-selling rap-rock band Linkin Park, recording on his own as Fort Minor. So hip-hop radio stations haven't been championing the song, and aren't likely to start. Despite all the rapping, is far more likely to show up on pop radio, or even rock radio. Mr. Shinoda will probably never make the cover of the hip-hop magazine XXL.

And maybe that shouldn't concern him. Decades ago rappers figured out that they could sell millions of records without going pop. But sometimes rappers do the opposite: they sell millions of records without, in a sense, going hip-hop.

Consider the Black Eyed Peas, the long-running — and excruciatingly cheerful — California alt-rap group. They spent years trying (and often failing) to win over the hip-hop establishment. And finally, in 2003, they hit gold (not to mention platinum and multiplatinum) with the album "Elephunk." But they did it without much help from the hip-hop world. Many radio stations still don't fully embrace the group, and hip-hop magazines remain downright skeptical.

Or consider Gorillaz, another hip-hop-influenced side project, this one led by Damon Albarn of the British band Blur. The most recent Gorillaz album, "Demon Days," included the hit hip-hop track "Feel Good Inc.," featuring rhymes from the veteran trio De La Soul. Thanks in large part to that song, the album has sold 1.8 million copies in America. Yet it was rock radio stations, not hip-hop stations, that played "Feel Good Inc.," giving De La Soul one of the biggest hits of its career.

In the case of Mr. Shinoda it should be said that he's not a very elegant rapper. No one who's accustomed to the sleek, slinky rhymes of T.I. (for example) is likely to be impressed by the workmanlike couplets he delivers on Fort Minor's 2005 debut album, "The Rising Tied" (Machine Shop/Warner Brothers).

Still, "The Rising Tied" isn't some guitar-heavy hybrid. It's a proper (though not very good) hip-hop album, with Jay-Z as executive producer and a handful of hip-hop guests (including Black Thought, from the Roots, and Common). There's something else at work here, though: a tacit reminder that hip-hop isn't merely a musical genre; it's also an identity. It has to do with fashion and slang and sensibility and background and marketing, not just music. With his baseball hat and emo lyrics and enunciated consonants, Mr. Shinoda doesn't fit. (And he knows better than to fake it.) Neither do the clean-cut break-dancers in the Black Eyed Peas, nor Mr. Albarn and his rapper collaborators.

This is partly a question of marketing, and it has something to do with race too. (Mr. Shinoda, who is part Japanese and part white, might be received slightly differently if he were black.) But culture, and not just race alone, explains who fits where: the black Dallas rapper Cowboy Troy will never take the hip-hop world by storm (he's marketed as a country act), whereas the white Houston rapper Paul Wall already has. Hip-hop is a radio format, a genre and a culture, and sometimes these overlapping definitions are hard to disentangle.

The continuing success of hip-hop has produced a curious disparity: it has become much easier to break out of the genre, but no easier to break in. (A few years from now Ludacris may — should, in fact — be a respected actor. But his "Hustle & Flow" co-star Terrence Howard could never be a respected rapper.) On the radio this means pop and rock fans are happy to hear rapping on their stations. But hip-hop fans don't necessarily want Mr. Shinoda on theirs.

Which isn't to say that they are narrow-minded. Quite the opposite: hip-hop's strong cultural identity has always encouraged a certain amount of musical diversity. Being a rapper isn't enough (as Mr. Shinoda could tell you), but these days it's also not a requirement. Some time ago — perhaps it was the early 1990's — hip-hop swallowed R&B whole; now crooners happily coexist with rappers. And many hip-hop stations also play reggae, some reggaetón, even a dash of soca. If you count samples, the playlists look even more eclectic: right now, one of the most-heard acts there is the French electronica duo Daft Punk, which is sampled on the Busta Rhymes hit "Touch It."

Of course, in a truly unusual case, these general rules won't be much help. It was always clear that Mr. Shinoda would never be embraced by hip-hop fans. But what about a different kind of genre crosser? What about the hypothetical case of a hip-hop producer turned alt-rock hero, teamed up with a Southern hip-hop pioneer turned soul singer?

In the next few weeks that hypothetical case will become a lot less hypothetical as American radio stations figure out what to do with "Crazy," the product of just such a union. The song, which has already topped the British charts, is the work of the producer Danger Mouse, who helped contributed to the Gorillaz album, and Cee-Lo, a founding member of the pioneering Atlanta rap group Goodie Mob. They adopted the name Gnarls Barkley and recorded an album, "St. Elsewhere" (Downtown/Atlantic), to be released Tuesday.

In "Crazy" Danger Mouse's hip-hop beat is brisk and sparse, cushioned by a string section that evokes 1970's soul; in Cee-Lo's falsetto you can hear faint echoes of his time with Goodie Mob. Two of the country's most influential radio stations have already played it: the rock station KROQ, in Los Angeles, and the hip-hop station Hot 97, in New York.

That means there are two questions surrounding the song. Will it be a hit in America? And if so, what kind?