As of today, PayPerPost.com bloggers will have to dislose that they are being paid for certain posts.
This comes hot on the heals of the Federal Trade Commission's December 11th statement about word-of-mouth marketing, that said that those who are paid to promote products to their peers, must disclose those relationships.
The disclosure statement does not have to appear within the blog post, but must be prominently displayed via a disclosure policy on the site.