The collective intelligence of consumers isn’t perfect—it’s just better than other forecasting tools. The catch is that to get good answers from consumers you need to ask the right kinds of questions; asking the market to predict how many copies a book will sell, which requires predicting how a wide readership will behave, is better than asking the market to predict which manuscript will get a book deal, which requires predicting the decisions of a small number of editors... Nobody knows anything. But everybody, it turns out, may know something.

The Science of Success: Financial Page: The New Yorker