This week, the list of performers at the giant Coachella music festival was released. The list of performers for 2011 include everyone from big names like platinum-selling Chicago-born rapper Kanye West to underground Rhode Island noise rock outfit Lightning Bolt.

But in the digital age, how visible is the line between the mainstream and underground? Arcade Fire, who headlines the festival on Saturday April 16, was just a few years ago an "indie" band — and perhaps one some would still argue represents something outside of the mainstream. Now they're headlining one of the largest outdoor music events in the country.

If you're a music fan, who in the lineup do you think is "mainstream," and who is "underground," and is that line blurring?

The same argument could be made for Kanye West, once an underground producer who has turned his prowess in the studio and knack for incredulous, out-of-breath rhymes into international stardom. And then there's The Strokes, a band whose incredibly catchy garage rock revival around the turn of the century was so meteoric that it seemed to create a tsunami of backlash that drove the band apart.

The three-day event is one of the country's largest outdoor festivals, effectively creating a tiny city in Southern California's desert each spring,  — last year drawing some 75,000 to each day's mix of stages and more. But some of the event's "biggest" name acts — from The National to PJ Harvey — came of age defining themselves as thoroughly outside the mainstream. As changes in the music industry come fast and furious, major gatekeepers like record labels and festival promoters seem hard-pressed to keep up. Is there still a clearly defined line between artists that are in the big time and artists that are best-kept secrets?

In her post about the Coachella list of performers, L.A. Times writer Ann Powers wrote the following:

"Last year's slump in concert ticket sales loosened the last solid brick in the foundation of the conventional music industry. Some festivals, including Coachella, still did relatively well, and in doing so, helped build excitement for new artists and maintain the value of more established ones. With the public's attitudes swiftly changing about what music is worth —  both financially and attention-wise — the success of an event such as Coachella can offset a lot of bad vibes and offer hope, which translates into concrete opportunities, for musicians and fans alike."

Bands like The Black Keys, who during 2004 released "Rubber Factory" to critical acclaim but only sold some 7,500 records in it's first week, are now being played on mainstream radio regularly. Pittsburg rapper Wiz Khalifa, who was just a few years ago playing to Brooklyn's smallish club Southpaw, now has a song with 25,000,000 views on YouTube. How quickly things change.