The Washington Post reports that the US Federal Trade Commission has issued new rules requiring bloggers to disclose that they've been paid to write a review or endorse a product:
"Bloggers who offer endorsements must disclose any payments they have
received from the subjects of their reviews or face penalties of up to
$11,000 per violation, the Federal Trade Commission said Monday…
…"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," the FTC said
in a release. "Thus, bloggers who make an endorsement must disclose the
material connections they share with the seller of the product or
service."
The new rules bring the US more into line with the EU where the Unfair Commercial Practices Directive (2007) has required similar transparency from bloggers and has effectively banned "astro-turfing".