There comes a time in the life span of any art form when becoming mainstream is a cause of celebration. (Happy to finally gain wider recognition, after laboring so hard in the hinterlands.) And then there is that other time when the realization comes crashing in that such mainstream acceptance is the best indication that the art is quickly losing its soul. Now is that time for hip-hop.

The Grammy Awards nominations (five each) for rappers Nelly and Eminem is the latest such signpost that it's time (again) to reevaluate where hip-hop stands relative to its humble beginnings and the mainstream's love/hate affair with the music, artists and culture. Nelly, a middle-class black kid from Saint Louis with a message of party-like-it's-1999, and Eminem, a white kid from Detroit whose lyrics open the front door on the pathologies of dysfunctional white America, are each a far cry from hip-hop's origins.

It may be hard to remember now amid the ghetto-fabulous and thugged-out madness, but hip-hop once gave public voice to the neglect and degradation facing young African-Americans who came of age in the '80s and '90s without a platform to articulate their concerns, fears or frustrations within a society whose lawmakers and very parents had written them off as a lost generation.

Joblessness, failing public education, a growing underground economy and an escalation of policing and incarceration as the order of the day are in part what gave hip-hop its wings. By the mid-'80s, rap groups like Eric B & Rakim were emphasizing the limited opportunities of young blacks in songs such as "Paid In Full": "Thinkin of a master plan/Cuz ain't nuthin but sweat inside my hand/So I dig into my pocket, all my money is spent/So I dig deeper but still comin up with lint."

Although these social and political realities haven't changed - in some cases, they've worsened - this platform has increasingly taken a back seat since hip-hop mainstream success started a decade ago. The message in the music is less important, and the dominant message that's in the music has changed. In "Cleaning Out My Closet," for instance, Eminem raps about his love for his daughter, Hailie, and his hatred for his mother: "And Hailie's getting so big now/you should see her/she's beautiful/But you'll never see her/she won't even be at your funeral/hahaha."

Most core hip-hop fans agree that Eminem is more hip-hop than Nelly when it comes to rap skills. Nelly, it seems, is selling more image than content - an R&B singer in hip-hop clothing, so to speak. The evidence is in the hook in the top-selling single "Hot In Herre: "It's gettin' hot in here (so hot)/So take off all your clothes/I am gettin' so hot (uh uh uh uh)/I wanna take my clothes off." There have been rappers before Nelly who lacked style and flow, but none has reached the multi-platinum heights and visibility Nelly enjoys.

Eminem on the other hand, though true to the game skill-wise, is trapped by America's long-standing racial politics. He's so conscious of not offending his black audience that he even fails to use black English, including the "n" word. In his lyrics and public reception, issues of youth alienation specific to white kids take center stage.

Ironically, both Eminem and Nelly are ensconced in "MC battles" - long a fixture in hip-hop where rap artists vie for lyrical supremacy. There's Eminem vs. Ray Benzino over the rapper's charge that Eminem is stealing black culture and taking sales from black artists. And then there's Nelly vs. KRS-One, a rap luminary who charges that Nelly's music isn't real hip-hop. So if not hip-hop, who do Eminem and Nelly represent?

"Most people in America, and to a large extent hip-hop audiences, have come to see the Grammys and other national institutions like BET and MTV as the standard-bearers for whether artists are good or not," says "Davey D" Cook, a Bay-area DJ, talk-show host and Web master of the influential hip-hop news site www.daveyd.com. "We forget that there is an agenda at work based upon a symbiotic relationship that music labels have with these mainstream outlets.

"Nelly and Eminem come to the table being distributed by the largest record companies in the world. So at the end of the day, influence and relationships will be maxed out to be sure [that] these artists get maximum exposure and inevitably this leads to greater popularity, which is what the Grammys are based on. Meanwhile, the hip-hop community has become so dependent on a few mainstream outlets that more underground artists like Jurassic 5, Blackalicious, Mr. Lif and Dilated Peoples, all of whom had incredible albums this year, have almost been forgotten - even among hip-hop audiences."

We've been here before - at this crossroads where mainstream and core hip-hop audiences come together and at the same time collide. Whether it was Lauryn Hill winning five Grammy awards in 1998, the media creation of the term "gangsta rap," the murders of Tupac and Notorious B.I.G. after the war of words on wax and in the media, or the 1980s emergence of the nationalistic message and images of Public Enemy, hip-hop has struggled to balance its mainstream success while remaining true to its earliest calling.

Through it all, hip-hop music has posted big sales (at times breathing new life into a withering music industry) and made its impression felt on the R&B, rock-and-roll and gospel charts. It's even made inroads into the worlds of fashion, film and advertising and much more. These mainstream appearances from Fifth Avenue to Hollywood and even Broadway have been widely applauded as evidence that hip-hop has arrived. Most certainly, this exposure has allowed artists to make more money and introduced to a wider audience some of the intricacies of what's going on in young black America.

But now those doing the celebrating, especially those who love, live and breathe the culture, are beginning to realize that the mainstreaming of hip-hop may have passed a point of no return. Rather than change the mainstream (the popular from-the-bottom-up assumption), the mainstream has changed hip-hop. More so, if the Nelly and Eminem Grammy nominations are any indication, the mainstreaming may, sooner than we think, mark the end of hip-hop as we know it.

Davey D insists that the Grammy audience, which will watch the awards ceremony next Sunday, is not the hip-hop audience and that the music will always be a voice to the voiceless, even if that voice is marginalized. "It might not show up on MTV and BET anymore, but it's up to us to skillfully and effectively use hip-hop as a healing voice and we must get away from MTV, BET and the Grammys of the world to represent that," he says.

I am very aware of the burgeoning underground hip-hop and spoken-word scenes, which in many cases remain true to the music's origins. To many hard-core hip-hop heads, they remain the genre's last hope. But the artists must do more to step up their game - to let the world tuning into hip-hop know that their message is part of what the music is all about- and the core hip-hop audiences must do more to support them and their message. If we fail to do this and the Eminems and Nellys of the world remain the public face of hip-hop for long, then I fear that hip-hop has lost not only its soul, but with it, it's very relevance.