We are smarter than me

I read the book "We are smarter than me".(Japanese name=クラウドソーシング)

This book was wrote about crowdsourcing. And It made me surprise, this book was writing for crowdsourcing. So, there are more than 4000 authors!!
How did authors write the book? It site is "we are smarter than me".

You know Wikipedia. It's one of most famous crowdsourcing. This book introduce good actual example with each theme. For example, theme of product development list P&G.

If you are interesting crowdsoursing, you should read this book. But it was released 2007, perhaps you read it.