Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Collective decision making

The thesis of this book is why (and in what situations) collective decision making surpasses expert knowledge. Since my work on spam filtration has been an exercise in collective decision making, I really appreciated the depth of analysis and ingenuity in formalization of the topic. The book is extremely content rich (and well written to boot!); I learned all sorts of stuff from it - design of Iowa Electronic Markets, how TV show ratings and advertisement pricing is computed, different kind of decision biases - cooperator bias and confirmation bias, and the many nuances of group dynamics. Highly recommended.