I think a better question than "how many minds produce knowledge" is "how many knowledge produce minds"? If we use knowledge to create minds we'd all be better off because we'd have cyborgs to do our laundry and we wouldn't have to pay people to clean our yards. and if these cyborgs ran off fusion powered reactors we could charge them up for weeks with spit or urine. so you'd really be killing several birds with one kidney stone. (putting to the side for the moment the ethical issues of having humanoid cyborgs see you naked in all your pallid glory.)

The book provides an excellent overview of various methods for knowledge aggregation and group collaboration, particularly statistical averaging, deliberation, prediction markets, wikis, open source projects, and blogs.

Sunstein provides a penetrating and balanced analysis of both the potential benefits and risks of each form of aggregation/collaboration, thus giving us some guidance on when to use (and not use) each method, and how to do it more effectively. I wish the book had provided clear summaries of that guidance, but it's still clear enough as is.

Sunstein is definitely a great writer. The result is a book which is easy and enjoyable to read, and the pages tend to fly by despite much of the material being a bit technical.

This book has started me thinking in new ways about some important issues, and it's not often that a book comes along which can do that. This is truly a book for our times, and is on the cutting edge on several fronts.

Very highly recommended for anyone who needs to, or wants to, deal with other people in order to get things done - in other words, everyone!

After reading Linked, and Freakonomics, this is helping me chase down yet more ideas about how the underlying networks on which society functions work. Or don't work.

In this delightful book, Cass R. Sunstein offers a cogent, compact and gently witty discussion of information sharing. His explanations of how different knowledge-aggregation processes work are extremely useful. They range from the theoretical (laying out the philosophical structures underpinning deliberation) to the practical (offering focused and specific suggestions for improvement). This certainly isn't the first book on how groups create knowledge - thinkers have rushed to make sense of the new possibilities that information technology presents. It is, however, one of the more quietly critical approaches, one that debunks extreme claims, points out the dangers that balance the often-trumpeted benefits and shares first-hand experiences. Sunstein is an enthusiast for certain types of collective information processing, but he is far from naïve. getAbstract recommends this book to managers interested in improving organizational decision making.

There's a lot of overlap between James Surowiecki's The Wisdom of Crowds and Infotopia, but Infotopia is a good deal more balanced and careful to avoid exaggeration. This makes Infotopia less exciting but more likely to convince a thoughtful reader. It devotes a good deal of attention to conditions which make groups less wise than individuals as well as conditions where groups outperform the best individuals.
Infotopia is directed at people who know little about this subject. I found hardly any new insights in it, and few ideas that I disagreed with. Some of its comments will seem too obvious to be worth mentioning to anyone who uses the web much. It's slightly better than Wisdom of Crowds, but if you've already read Wisdom of Crowds you'll get little out of Infotopia.