Scientist proposes replacing peer review with something like Reddit

At Genomes Unzipped, Joe Pickrell, a graduate student in genetics at the University of Chicago, makes a case for replacing the traditional peer review system for scientific publications with something more akin to social networking. Or, really, a professional version of Reddit, plus some deep search features. Not having dealt with the peer-review system myself, I'm curious what the scientists out there think. Good idea? Bad idea? Good idea for some fields, bad idea for others? (Via Daniel MacArthur)