For one of its latest advertising campaigns, T-Mobile enlisted a creative team that it believed would best reach its young, peer-influenced customers—its users.

"With so many ways for companies to reach them, they're almost overloaded," said Melinda McCrocklin, T-Mobile's advertising manager. "We want to make sure our message breaks through."

So McCrocklin and her team in Bellevue, Washington, created a contest that invites customers to build 30-second spots using graphics, music, and footage of basketball stars Charles Barkley and Dwayne Wade that T-Mobile provided on its site. The lure? A promise to broadcast the winning short during this season's N.B.A. playoffs.

"We look at this as getting another creative idea," McCrocklin said. "And if something's there, we'll explore."

While the holy grail of advertising has long been thought to be data targeting—finding the right ad for the right viewer—some brands are literally handing the reins to customers, letting viewers create their own ad messages, or even pick the spots they want to watch.

Not surprisingly, two emerging TV networks, one on cable and one on the Web, are pioneering this ad trend.

Current TV, Al Gore's youth-oriented cable network launched viewer-created advertising messages, or VCAMs, as soon as the channel went live in August 2005. They give viewers the opportunity to help create the ad message served to them.

Then NBC Universal and News Corp. joined forces to build Hulu.com, which streams top shows like Heroes and Medium, as well as more shelf-worn movies like Mulholland Drive, to viewers for free. It went live last month and soon plans to let viewers pick the ads they watch from a pool offered by a single brand: say, a car company or cosmetics giant.

Jean-Paul Colaco, senior vice president of advertising with Hulu.com, said that a major car company will be the first to test the waters. He declined to name the sponsor.

"Users will define the advertising experience they want," Colaco said. "If you increase the amount of choice, [brands] can get direct feedback on the ads and know within the first two days if it's successful."

Hulu declined to elaborate on what it charges its clients for this new service. But it seems safe to assume that advertisers are being asked to pay a premium for this kind of targeted result—particularly since it can take 12 to 16 weeks to create the user-driven contest and get it on the air.

Current TV marketing executive Joshua Katz said that clients who want to run a VCAM on his channel "have to bring a certain amount of money to us."

Since YouTube's skyrocketing success, it's easy to find young, Web-savvy users willing to make short clips they hope their peers will laud. The difference with VCAMs is that the shorts are ads that brands usually have to pay a lot to create.

Current has run 26 VCAM contests since launching in August 2005, and it attracts anywhere from 100 to 600 submissions, says Katz. One such spot included Tyson Ibele's winning spot in 2005 for Sony that featured the technology giant's products robotically morphing into each other.

It's easy to see why Ibele won. The ad has all the simplicity of a MacBook Air but evokes the fun of a Transformer toy—a cultural touchstone for the target audience.

For this spot, Ibele walked away with the grand sum of $1,000—about what a commercial television director earns in one hour on a set. Now a film-studies and production major at Victoria University of Wellington in New Zealand, Ibele, a Canadian, works part-time building animation for the Minneapolis-based online creative agency MAKE.

Ibele acknowledges that his Sony ad generated some nice professional buzz for him—although he notes that Sony made out fairly well, too. "Companies are definitely getting a free ride," he said. "They pay—what, $100,000?—to make a 30-second spot, and here I'm paid 1 percent of that as a prize."

Companies can pay a whole lot more than that for a concept that runs across all media—such as advertising agency TBWA's "PC and Mac" campaign for Apple. Still, even the ad giant plucked an iPod spot off YouTube last fall, created in a day by an 18-year-old in Britain, and retooled it for network television.

Notably, though, Apple hasn't fired its agency in favor of YouTube contributors—yet. However fans with creative ideas, and some digital production ability, now have several avenues they can use to push their ideas in front of brands—and bypass those Herman Miller-designed agencies.

Brands can already pick up a bargain or two right now at Current. Since Ibele's win, the channel has raised its rates a bit—now paying winners $2,500 for their spot, according to Katz. If the ad runs on another website, it earns the creator another $5,000. If it airs during a commercial break for Gossip Girl, a budding adman can count on $15,000. (Current caps its payouts at $60,000.)

"We have the right to exploit [the VCAM], but with every conceived usage you get compensation," says Katz. Still, even he admits that $60,000 for a full campaign is a bargain-basement fee. "If advertisers could hit upon an idea for all platforms for just $60,000?" Katz asks. "They'd be running to me."

The million-dollar question is, of course, do these viewer-created ads actually work? And do viewers really pay any more attention to ads they've selected over those they're spoon fed? Katz says viewers pick Content's VCAMs nine to one over regular spots, according to its proprietary research.

Hulu says the launch of its movie-selector option, which went live at the same time the site did last month, has been an overwhelming success with viewers preferring to watch a movie ad of their choice instead of regular commercial breaks while streaming a video from Hulu's library.

Proponents and viewers of user-created programs, whether it's entertainment or advertising, believe this is a trend that's just beginning.

"People pay attention when they can see it's made by a human being rather than an agency," says Ibele, who is both a creator and part of the target audience. "And the viral aspect of this will get even more people interested."