I really like this Jaron Lanier essay.

The collective is more likely to be smart when it isn’t defining its own questions, when the goodness of an answer can be evaluated by a simple result (such as a single numeric value,) and when the information system which informs the collective is filtered by a quality control mechanism that relies on individuals to a high degree. Under those circumstances, a collective can be smarter than a person. Break any one of those conditions and the collective becomes unreliable or worse.

Meanwhile, an individual best achieves optimal stupidity on those rare occasions when one is both given substantial powers and insulated from the results of his or her actions.

Read the whole thing.