A quibble with the author's impression of peer review:<p><i>As we know, the process of submitting to a scientific journal has, besides the diffusion of one’s results to the community, the aim of verifying those results. Here, such an approach was made impossible by Perelman, so some independent groups of scholars set at the highly difficult task to understand, complete, verify, and explain his work.</i><p>Peer review does not "verify results"; peer review is there to make sure there are no serious and obvious flaws. Duplication of studies and collection of additional data / use of other techniques is what verifies results.<p>It is possible Perelman's papers received a more rigorous review because they were not peer reviewed – giving people incentive to dig into the details, perhaps more than they would have if the papers had appeared in a journal. But, given the signficance of the problem he was attacking, I suspect the papers not being in a peer-reviewed journal made little difference, in terms of how much effort was expended to check his proofs.