CNet:

"To Berkeley's Mulligan, standing up for FatWallet was a way to set a good precedent the next time a similar situation arises.

"We certainly see plenty of uses of the DMCA that appear to be appropriate," Mulligan said. "But we also see notices under the DMCA that are alleging trade secret or trademark. The DMCA gives copyright holders, businesses, people who are alleging copyright infringement a really enormous tool. They can take information down by a mere allegation. I think it's important that FatWallet is pushing back not just on the subpoena but saying this is an abuse of the law."

[...]

In stiffly worded letters sent to the other companies, FatWallet's attorneys said that false claims of copyright made the retailers liable for damages. "Sanctions for perjury may also be applicable, as well as penalties for violations of the ethical canons governing attorneys," the letters said."

You know where not to shop in the weeks to come. See also: Bargain Shoppers Chilled by Retailers' DMCA Threats