FTC (Federal Trade Commission) might get involved with paid posts. The FTC handles consumer complaints about products. I don’t know if any consumer has complained about paid post, but the FTC doesn’t like bloggers doing paid posts. According to Businessweek,
This summer, the government agency is expected to issue new advertising guidelines that will require bloggers to disclose when they’re writing about a sponsor’s product and voicing opinions that aren’t their own. The new FTC guidelines say that blog authors should disclose when they’re being compensated by an advertiser to discuss a product.
So basically the FTC wants bloggers to disclose that it is a paid plugin. But at times, most paid to blog or paid to post site requires bloggers not to disclose it is a paid post. Well, I think this guidelines would be for the popular blogs. Bloggers with small blog should have no worries because they wouldn’t be seen by FTC. Only Google that might see their blogs. Google would reduce your site PR if it catches you doing paid post.
I don’t see anything wrong with paid post. The only problem would be if the review is postive, but the blogger hasn’t tried the product. If the blogger has tried the product, he can give a postive or neutral review. When I was doing paid review, I prefer writing neutral post because I haven’t tried the product. I don’t want to wast my time lookng for positive reviews other blogs have written and try to compose my own. That is time wasting and stressful.