(FORTUNE Magazine) – IT'S BEEN A BRUTAL YEAR for Chevrolet. Bacardi is in serious trouble, and Lamborghini is being lapped by Rolls-Royce. We're not talking about their businesses, mind you. No, the icons have all taken a tumble on the American Brandstand countdown, which tallies the number of times a brand is mentioned in popular music. Forget E.F. Hutton. When Snoop Dogg speaks, people listen.

Agenda Inc., a pop culture-focused research and marketing firm in San Francisco, started compiling the Brandstand in January 2003. "We did this to show people how ubiquitous brands are in pop culture and what opportunities there are [to exploit the presence]," says Agenda president Lucian James.

Witness the rankings through the third quarter of 2004, available at www.americanbrandstand.com. The top ten are dominated by old-money luxe names like Jaguar, Lexus, and cognac Hennessy, which occupies the top spot with 52 mentions. (A brand earns one mention for every week a song in which its name is dropped sits on the Billboard top 20, so 52 mentions doesn't equal name-dropping in 52 songs.) "We've kept our eye on it for a while. It's a novelty I guess," says Dexter King, senior brand manager for Hennessy importer Schieffelin & Somerset. But King says there's no doubt the free publicity has boosted sales. "These rappers do an amazing amount of marketing for us," he says.

Other brands haven't been so lucky. Mercedes has dropped from No. 1 in 2003 to No. 5 currently, and brands such as Manolo Blahnik (No. 15 in 2003) and Kmart (No. 19) have fallen off altogether. Is there a strategy in place to get back on the countdown? Says Kmart spokesperson Caryn Klebba: "Well, since we didn't know we were on it, I'd say there isn't." -- Reed Tucker