Many years ago there was a kind of gentleman's agreement in the advertising industry that you didn't bad-mouth the competition. Not anymore. Tune in to the TV commercial breaks on any given night and you may see Coke denigrating Pepsi, Nike bashing Reebok, Chevy trashing Ford. Try this approach in the fossil fuel industry, however, and all hell may break loose.

Earlier this year, a group calling itself the Clean Sky Coalition took out a string of ads in the Washington Post, the Wall Street Journal, and several major Texas newspapers. These don't come cheap: A quarter-page in the Post can run to $30,000. Under the slogan "Face It: Coal Is Filthy," the coalition attacked a plan by the TXU Corp. to build 11 new coal-fired power plants in Texas.

West Virginia, bastion of the coal industry, was not amused. The National Mining Association lodged a vehement protest. But there was one mystery: Who was behind this fragrantly named coalition, which listed neither its address nor its backers? The answer, it turned out, was Oklahoma-based Chesapeake Energy, the country’s third-largest natural gas company.

End of the story: Chesapeake bowed to big coal and pulled the ads with profuse apologies. Moral of the story: something about the pot calling the kettle black?