1) There is a shocking amount of credible market research that all point towards the growing and dominant power of consumer reviews. With better access to information, multiple choices of goods and services, and the opportunity to share experiences with a single click, consumers have become empowered to do their own research on purchases.
There has also been a strong prevailing sentiment that the press cannot be trusted as these reviews are incredibly biased due to fear of losing continued sponsorship. I would expand more into it but these studies explain it better and more comprehensively than I ever could: The Deloitte Consumer Review and the "Buy It, Try It, Rate It" study from Weber Shandwick.
2) We have multiple measures in place to monitor and ensure quality reviews that aren't driven just to receive the rebate itself. Such measures include a set and structured product reviewing process, and a user-ranking system that rewards high quality reviews. We plan to heavily curate our user base through similar strategies from companies such as Quora and Yelp.