A Review By Any Other Name

I have noticed lately that there seems to be a growing trend with Blog review sites though with a twist. They want you to pay them for the review, so far the price range I have seen was from 40USD to 500USD.

This poses an interesting question when is a review not a review? In my opinion when you pay for it, the review becomes something else, and that's called an advertisement unless it is disclosed in the review that it has been payed for by the owner, I just don't see a way around it not being biased. So let me know what are your thoughts on this trend?