James Surowiecki

... under the right circumstances, groups are remarkably intelligent, and are often smarter than the smartest people in them. Groups do not need to be dominated by exceptionally intelligent people in order to be smart. Even if most of the people within a group are not especially well-informed or rational, it can still reach a collectively wise decision. This is a good thing, since human beings are not perfectly designed decision makers. Instead, we are what economist Herbert Simon called “boundedly rational.” We generally have less information than we‘d like. We have limited foresight into the future. Most of us lack the ability — and the desire — to make sophisticated cost-benefit calculations. Instead of insisting on finding the best possible decision, we will often accept the one that seems good enough. And often we let emotion affect our judgment. Yet despite all these limitations, when our imperfect judgments are aggregated in the right way, our collective intelligence is often excellent.

This intelligence, or what I’ll call "the wisdom of crowds," is at work in the world in many different guises. It's the reason the Internet search engine Google can scan a billion Web pages and find the one page that has the exact piece of information you were looking for. ...