Amazon (AMZN) is going to war against fraudulent product reviewers on its site. The e-commerce giant is making an effort to regain a sense of authentic user feedback by suing over 1,000 people offering to write paid reviews for sellers. Many reviewers are advertising their services for as little as $5 per write up and providing fake 5 star testimonials for products they didn't purchase and have never used. Some companies have also been accused of trying to boost sales by commissioning the bogus reviewers. Companies such as Yelp (YELP) and Trip Advisor (TRIP) have also struggled to crack down on phony reviewers, resorting to specialized algorithms to stop suspected phony reviewers.