this story regarding how advertisers are now suing one another over claims made in their ads; the issue is that an advertiser may lose market share as a result of a particular claim made by a competitor. Consumers have learned to accept that advertisers overstate their claims, even though to some this may seem unethical. Advertisers have the opportunity to take their issue to the Better Business Bureau’s National Advertising Division, or they can directly sue the competitor to either get the offending ad withdrawn or for compensatory damages when they can prove market share has been affected, and of course that the claim is unsubstantiated.
When it comes to comparative advertising, the FTC has actually encouraged advertisers to directly compare the attributes of their product or service against a competitor's. The government passed a regulation back in 1978 to that effect, and as a result we’ve seen over the years campaigns like the Pepsi Challenge, among others.
The Times reports that a number of brands are going after competitors--Campbell and Progresso to name one--and that this is a response to a weak economy. In other words, no one can afford to lose market share. Read the article and look at the accompanying video to consider whether you think comparative claims are an ethic issue or a legal issue?