An upstart group of activists, Coal Kills Kids, aided by the Yes Men — a tech-savvy group famous for skewering corporate America — launched a bogus campaign claiming the company was set to offer free kid-themed inhalers and coupons for asthma medication to children who live around coal-fired power plants.

St. Louis-based Peabody, the world's largest private-sector coal miner, reacted to the PR attack in typical corporate fashion: with a press release, lawyers and indignation.

"We're continuing to pursue legal remedies for what, at its core, is identity theft, company spokesman Vic Svec said. "It shouldn't be allowed, or even winked at, in any form."

In an era when anyone with an opinion can create an elaborate website — and pepper links throughout social media networks instantly — companies face a newly complicated landscape in crisis public relations. Such attacks have become "the new normal," according to Harlan Loeb, executive vice president for U.S. Crisis & Issues Management practices at public relations firm Edelman in Chicago. "Unfortunately, it is a growing scourge of sorts in various forms."

Companies should now expect to be targeted by hoaxes — and prepare to respond quickly, using the same digital tools, including social media, he said. Loeb, a lawyer who also teaches a course at Northwestern University Law School, said the potential legal consequences of the Yes Men's hijinks aren't so clear.

"But my guess is that we will soon see a judicial ruling that suggests, if there was intent to convey misleading information, that constitutes a tort," he said.

Though the Peabody prank was quickly judged a hoax, it nonetheless made a splash in news outlets from CNN and the Wall Street Journal to Forbes and Rolling Stone. It is the latest caper by activists who are increasingly making use of the Web and social media to generate publicity and embarrass corporate victims.

Before Peabody, the Yes Men targeted General Electric Co. with a fake press release claiming the conglomerate was returning $3 billion to the U.S. Treasury. Then there was the hoax claiming that pipeline operator Enbridge's planned to clean up oil spills with human hair.

Peabody issued a statement within hours identifying the website and press release as fakes. Its attorneys followed up with a letter to the activist groups the next day, asking them to take down the website within 24 hours.

The San Francisco-based Electronic Frontier Foundation, which represents Jacques Servin, a leader of the Yes Men, says the threat is without merit and protected by the First Amendment.

"The site is designed to engage in and promote political commentary," the foundation said in a letter to the coal producer. "It clearly presents a satirical perspective of Peabody's political positions and practices, as well as the coal industry in general."