A WebmasterWorld discussion brought to light a manipulative spam technique that was reported to be flourishing in Google. It involves competitors creating fake review sites to rank in Google. These review sites not only promote their own products, a publisher is reporting that the fake sites are also saying bad things and giving poor reviews.
The spam technique consists of creating fake product review sites created by the sellers of the products that are being reviewed. It was reported that some of the sites spread negative information about competitor products.