Surveys paint a disconcerting picture of their impact. An April 2012 study from Nielsen found online reviews were the second most trusted form of advertising after word-of-mouth by family and friends. Yet the technology research firm Gartner estimates that by 2014, some 15 percent of online reviews will be fake. And a 2011 study from Harvard Business School found that a one-star increase in a Yelp rating increased a restaurant's revenue up to 9 percent. Being tricked into buying a lousy sandwich is not the end of the world. But reviews of doctors, lawyers, mechanics and construction companies influence important transactions. Can the fake reviews be stopped? The Federal Trade Commission released new guidelines in March trying to address all the new ways consumers get information about purchases. Under the guidelines, if someone is compensated for writing a review of a business, they must disclose the relationship. Get the full story at the San Francisco Chronicle