If you're talking specifically about Foursquare, I dunno, but pretty much any news story about Yelp in the past decade covers it, e.g. http://consumerist.com/20

If you're talking specifically about Foursquare, I dunno, but pretty much any news story about Yelp in the past decade covers it, e.g. http://consumerist.com/2014/04/04/yelps-controversial-business-tactics-contribute-to-2000-complaints-received-by-ftc/ http://consumerist.com/2014/04/04/yelps-controversial-busine... "The number of complaints might not come as a surprise to those who have followed the numerous lawsuits and allegations of extorting money from businesses to remove negative reviews." "For years, businesses have claimed that negative reviews pop-up on their Yelp pages after they’ve declined to purchase advertising with the company."