The author makes an interesting case for niche' markets in selling to peer-to-peer type social networking customer base. His observations are, in my opinion, a result of years of riding the bleeding edge by many social networking companies, whose ideas have been later embedded within "mainstream" internet shopping portals. Epinions comes to mind as one, Gomez.com, and many more. The author used Amazon.com's "Readers who read this book, also liked or bought..."feature, as an example on how P2P and social networking is changing the marketting and PR game. Does this mean it is time for Diversification for PR firms??
Despite the author's best intentions, I cannot help but imagine, that eventually, just like press media, this domain will be cornered by a handful of "name-brand" PR sites. Internet-savvy shoppers however will continue to use features such as Amazon.com's recommended list.