So the techno-utopians were at least half right: The Internet has helped a lot of people make better decisions about which movies to watch, where to eat and where to sleep. But on the other side of any sophisticated system designed to produce fair and honest appraisals will be equally resourceful schemers looking to game the system.
In fact, given the subversive efforts of those working to undermine honest rating systems, it's a testament to the fundamental good nature and public spiritedness of human beings that crowdsourced evaluation doesn't unravel completely. The only way group feedback can survive is if there is a massive counterweight of reviewers taking the time to provide honest feedback despite the complete absence of economic incentives for doing so.
Fisman is a professor of social enterprise and director of the Social Enterprise Program at the Columbia Business School.