Earlier today, the FTC published New Laws regarding testimonial advertisements on web, focusing on blogs and social media. While these changes include needed changes such as no longer allowing "results not typical" (they now cannot use unusual results) in advertisements, they also introduce wording regarding personal bloggers endorsing products on their blog in return for some item of material value (money, products, etc.).
The statements regarding bloggers are quite controversial. There are many potential problems as well as many things you probably have not thought of about what this affects. As many of the bloggers will know, a good way to make money off your blog is to endorse products and get money from affiliate links. While most of the time, people have disclaimers on those posts, these new rules now make it illegal to not have a disclaimer, punishable with up to a $11,000 fine. Similarly, bloggers who review products now must tell which products they got for free, it is no longer just etiquette, it is the law.
Finally, the new laws even extend to social media such as Facebook and Twitter. Now, if you are obtaining any item of material value from a company, any time you say anything good about them, you also have to tag on a disclaimer. This includes "endorsements outside the context of traditional ads, such as on talk shows or in social media." From this follows that you could be breaking the law by telling people how much you like your copy of Windows 7 (which you got by hosting a release party) or how much you like your newly redone driveway (which they gave you a discount on to tell others about them). This also pretty much bans you from becoming a ‘fan’ of the company on Facebook, as you would have to tag on a disclaimer anywhere your picture showed up advertising the product (which Facebook does by default for pages you ‘fan’).