Environmentalists use editing tools provided by carmaker to bash the company on global warming.
Last month, General Motors launched a contest to see which member of the public could craft the best commercial for the Chevy Tahoe, a sports utility vehicle. At ChevyApprentice.com, visitors could choose from a range of soundtracks and video clips of the Tahoe traveling through different terrains. They also had the option of writing their own text to accompany the video and music.
Chevy gets trashed in commercial contest
Chevrolet let users make ads for the Chevy Tahoe, but a couple slipped by depicting SUV as a gas-guzzling machine.
One of the videos circulating around the Web featured shots of the Tahoe zooming through snow, mountains and desert. Over the video appeared the words: "Global warming isn't a pretty SUV ad. It's a frightening reality."
Another commercial entry read: "Temperatures are rising. The polar ice caps are melting. Global warming is happening now. What will you tell your kids that you drove?"
Calls to General Motors were not immediately returned on Friday.
Video is rapidly becoming a powerful communication tool on the Web, thanks primarily to improved download speeds. In General Motors' case, an effort to generate customer-created content gave protesters the tools they needed to create their own messages.
Just how many similar ads were created and are spreading via the Internet is unclear. In one of the three protest commercials viewed by CNET News.com, the text refers viewers to ExxposeExxon.com, the Web site created by environmental groups to fight proposed oil drilling in the Arctic National Wildlife refuge, according to Shawnee Hoover, campaign director for ExxposeExxon.com, a coalition that includes well-known advocacy groups such as Greenpeace and MoveOn.org.
She acknowledged that a member of the group is responsible for creating two of the commercials but ExxposeExxon.com itself had nothing to do with them.
"We have hundreds of thousands of people who are boycotting Exxon," Hoover said. "We had nothing to do with the commercials, but we thought it was a great idea."