I never really liked this type of marketing. Big companies like Sony for instance have gone to the lengths of creating ENTIRE websites like these to promote their products, but they don't tell you that they make the websites, and make up all the user reviews.
Some global media companies pay people to surf forums for movie reviews, or book reviews, and post positive reviews for products they them selves have never used.
to the end user they look genuine.
A good example is Gamestop.com You can go to their website and look at a video game that has not been released yet. There are all reayd positive reviews for a product that isnt on the shelf.