The Federal Trade Commission will require bloggers to clearly disclose any freebies or payments they get from companies for reviewing their products.
It is the first time since 1980 that the commission has revised its guidelines on endorsements and testimonials, and the first time the rules have covered bloggers.
But the commission stopped short Monday of specifying how bloggers must disclose any conflicts of interest.
The FTC said its commissioners voted 4-0 to approve the final guidelines, which had been expected. Penalties include up to $11,000 in fines per violation.
The rules take effect Dec. 1.