LAS VEGAS >> Jay-Z rapped about his beef with corporate radio in the monster jam "99 Problems," noting that stations won’t play his hits if he doesn’t do their shows. But on Friday, he played savior to radio station giant Clear Channel, headlining a two-night concert billed as the largest in radio history and a major step toward keeping the industry alive in the dot-com era.

The rapper bounced across a stage outfitted with two drum sets and two guitarists as he spit out his biggest hits and swung the two oversized gold chains hanging from his neck. It was the final performance of a night that saw confetti bombs dust the shoulders of pop sensations Kelly Clarkson, the Black Eyed Peas, Bruno Mars and Carrie Underwood. The spectacle was scheduled to continue Saturday night, with headliners Lady Gaga, Jennifer Lopez, Sting and Steven Tyler.

The star-studded lineup usually reserved for charity concerts was a marketing blitz that drew thousands to the MGM Grand Garden Arena in Las Vegas and was broadcast to more than 10 million radio listeners across the country. Its intended beneficiary was iHeartRadio, Clear Channel’s revamped free personalized music website that allows users to create custom radio stations and is meant to compete with the web’s most popular online music services, especially Pandora.

"This is our coming out party," said Bob Pittman, chairman of media and entertainment platforms for Clear Channel Communications Inc. "What makes the festival so unusual is every act is a headliner."

The concert hosted by Ryan Seacrest began with the Black Eyed Peas taking the stage in a fit of confetti and pyrotechnics. Fergie, the pop group’s only female member, snaked across the stage in black shorts that revealed her butt cheeks.

Concertgoers also waved their glowing cellphones in the air for Alicia Keys, Coldplay and rock band Jane’s Addiction during the nearly five-hour concert. In a nod to Las Vegas’ showgirl tradition, two feather-frocked, barely clad dancers frolicked across the stage as Jane’s Addiction performed.

Coldplay frontman Chris Martin and Mars each paid tribute to late British soul diva Amy Winehouse, with Mars performing Winehouse’s "Valerie" as a brass quartet waved their horns in unison, and Martin urging the packed arena to join him in a mournful chorus of her prophetic hit "Rehab."

Fireworks later dusted the stage as Martin twirled his arms, curved his hips and then rolled over backward in a flurry of dance. A psychedelic piano joined him on stage.

Keys and Jay-Z performed the only duet of the night, a sequin-drenched performance of their hit "Empire State of Mind." Jay-Z thanked the crowd for singing along.

"I know I am on the West Coast," he said.

The mix of country, rock, rap, pop and R&B was a deliberate nod to the broad array of music available on iHeartRadio, Pittman said. The revamped website allows listeners to hear the feeds of more than 800 stations or create individualized channels that stream music along specific genres. Listeners can access 400,000 artists and 11 million tracks, millions more than Pandora.

Pandora launched in 2005, offering revolutionary computer formulas that create personalized song lists based on each users’ tastes. It has grown to more than 30 million listeners each month.

Clear Channel is not about to cede its web listeners to another company. When it announced the iHeartRadio revamp, it had about 27 million listeners per month, just short of Pandora’s reach. This month, iHeartRadio climbed to 30 million listeners each month, Pittman said. In all, Clear Channel reaches 237 million monthly listeners over traditional radio airwaves, ensuring that the company will be able to promote the site to millions of potential consumers.

Clear Channel will also turn to the music site to identify emerging artists ready for traditional radio and get user feedback.

"It’s a way for us to discover more artists," Pittman said.

The beta site launched Sept. 8. This weekend’s two-day festival marks the site’s grand opening.

It’s unclear whether the multi-day concert will drive listeners to iHeartRadio. Tickets sold out in 10 minutes.

Livio Lippetti, of Huntington Beach, Calif., traveled to Las Vegas to see Bruno Mars and the other headliners Friday. He said he had never heard of the website, despite advertisements promoting the site flashing over the stage after each act. He said he prefers Sirius XM Radio Inc.’s satellite service to web stations.

"I’m all about XM," he said.