Why buying social media reviews is a recipe for marketing disaster

Most of my family, friends and work colleagues pretty much turn to the Internet for a quick and unbiased opinion before splashing the cash on a product or service these days. And why wouldn't they, after all the majority of reviews will be from people sharing their real world experiences of those goods rather than relying upon marketing materials and 'advertorials'. However, according to Gartner, paid for social media ratings and reviews will account for as much as 15% of all reviews by 2014.