However, the commission has a broad definition of what constitutes an endorsement.

“The revised Guides specify that while decisions will be reached on a case-by-case basis, the post of a blogger who receives cash or in-kind payment to review a product is considered an endorsement,” said a release by the FTC.

This could be a legal nightmare for reviewers, who often rely on manufacturers to lend the products for review. In fact, most reviewers depend on this system, with a few rare exceptions such as This Week in Tech’s Leo Laporte. Even then, he doesn’t buy every single product he reviews.

This is the first time the guidelines have been updated since 1980. Under those rules, endorsements were considered perfectly fine, as long as the paid endorsers included the line, “results not typical,” but the new mandate removes that safe harbor.

Since this only applies to bloggers residing within the United States, it’s hard to imagine this will do much to curtail astroturfing. And it’s uncertain if this will apply to traditional reporters, however celebrity endorsements are specifically mentioned.

The FTC says that it will enforce the new rules on a “case-by-case basis.” I can’t help but wonder if this will create a chilling effect for American bloggers.

Read a PDF of the new regulations.

Update 20:25 CST: Leo Laporte commented about this on Twitter: “…Fantastic news! I’m clean. Are you?” [In response to @wa4hrk]