The FTC (Federal Trade Commission) requires bloggers to clearly disclose any "material connection" to an advertiser, including payments for an endorsement or free product. The TFC voted 4:0 for the new regulation (revised guide 81 pg, PDF) which goes into effect Dec. 1, and penalties include 11,000 USD in fines per violation.
Quote From adage.com
Specifically covered in the new rules is the use of social media, such as Twitter, by celebrities to endorse a product. That's now a no-no unless the commercial relationship is disclosed. So, too, are celebrity mentions of products in other media, such as talk shows.
But the new rules on blogging will have the farthest-reaching influence. They are, in effect, the first rules imposed on a general public that no longer needs access to TV, print or radio to publish opinions or create a personal media channel.
"In 1980 most of all advertising was disseminated by the advertisers themselves; today a good part of that advertising is being disseminated by users," said Richard Cleland, assistant director- division of advertising practices at the FTC ... via / more
BBC News: New rules to end 'blogger payola'