There's a whole lot of information in this book, more than I can possibly summarize or even remember. There's a general history of curation (covering, among other things, the history of the Dewey Decimal system). There are examples of websites that have been hugely successful in the field of content curation (the Huffington Post, for example). There's some lip service paid to the process whereby the individual can contribute curation to the internet, but this is really more of a "why to" book than a "how to."
In short, it's really difficult for me to figure out exactly who this book was written for. It seems to me that if you're interested in this stuff, you already know most of what Rosenbaum is telling us. And if you don't know, you probably aren't all that interested.