FTC is regulating blogger endorsements.

Disclosure requirements. Blech.

These examples address what constitutes an endorsement when the message is conveyed by bloggers or other "word-of-mouth" marketers. 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. Thus, bloggers who make an endorsement must disclose the material connections they share with the seller of the product or service.

Much more at the link. I think this is all stuff that I wouldn't be doing in the first place. If anything, I'd blog about getting the stuff and not review it.