By now you've probably seen that guy on TV rapping along with the sound of his beeping stove, crafting a rhyme in praise of a jar of mayonnaise. This grainy home-video footage was not the brainchild of an urban-savvy ad exec, but the result of the company opening up its marketing to a public competition.

Hellmann's Mayonnaise is riding the newest tech trend of "user-generated content," and is soliciting user-created ads at www.hellmanns.ca. Marketing is the latest field to make use of cheap digital video cameras and editing software, and content made by the very people who make up their target markets.

Converse was one of the first companies to capitalize on people's love of its products, soliciting 24-second shorts about classic Chuck Taylors. Over 1,500 entries were submitted, and 40 were edited into screened ads.

But is it ethical for companies making millions to hawk their products through the work of their own fans, offering little or no compensation? Converse paid its winners $10,000 for a winning clip, which might seem like a lot until you consider the millions it usually spends to generate an ad spot. The Hellmann's guy got $750 for his efforts.

A recent article in Fast Company, a mag for entrepreneurs and business people working for themselves, suggests people look past monetary issues and consider this user-designed fad as an opportunity for hungry editors and ad execs to make a name for themselves. In this sense, the Internet has become a new arena for a Darwinian survival-of-the-fittest-marketing-strategist struggle.

David Karlsberg, one of the winners of the Converse competition, said, "I probably would have paid $10,000 to have some of my commercials on TV. It really opened a lot of doors."

Threadless, an online T-shirt design company, gets graphic artists to submit designs that are then rated by site visitors. The winners get their T-shirts printed in limited editions and $1,000 in cash and prizes. Regular contributors have online portfolios, which many consider more valuable than the prize money.

The cable network Current TV, which relies on user-generated content for up to one-third of its programming, has been holding $1,000 contests for the best ads for certain brands. Companies like Sony, L'Oreal and Toyota are flocking to Current TV, and the result is a bizarre scenario where companies just sit back and watch consumers create their ad campaigns.

Businesses have since sprung up to cater to this trend, acting as brokers between companies and their customers/marketers. Adcandy.com and Revver.com stage competitions for slogans, ads and video clips.

But there's been an inevitable backlash. A few months ago, Chevrolet provided a whole bank of stock shots and music on its website for fans to edit together in praise of the new Chevy Tahoe. It received over 21,000 submissions, posted online for the world to see.

Once fans voted on their favourites, however, Chevy scrambled to do damage control. The most popular spots profiled the SUV in an ironic light, complete with text condemning the truck's impact on the environment floating over shots of the Tahoe bombing through pristine wilderness. Check out the best of the so-called "attack ads" at www.news.com.com/ 1606-2_3-6056633.html.

It seems that relying on consumers to do the dirty work of advertising in an increasingly cynical marketplace has a high price tag after all.