A new mechanism has emerged to help B2B buyers who are searching online for products and solutions:  Ratings and reviews sites, where searchers can find out what their peers are saying about prospective products and suppliers, and compare product features head to head.  Just as consumers use Yelp and TripAdvisor, business buyers can check out G2Crowd, TrustRadius, Clutch.co, Capterra and others.    These sites work best in fragmented markets, where it can be hard to stand out among the many…