Seeing as how it is of interest, if I may trouble the crowd here with yet another summary, "The Wisdom of Crowds" (which is actually sitting on my desk, next to "Good to Great") says that to have a "smart" crowd, these conditions must apply:
- Independence - people don't look at one another's answers prior to submitting their own.
- Diversity of opinion
- Decentralization
- A way to aggregate the results
The independence thing is the problem with digg/reddit/yc.news etc... - instead of a bunch of people voting on their own, and then seeing what comes out, you see ahead of time how everyone else has voted, and reddit groupthink ensues. News.yc is better because of the high quality of the people, not the algorithm.
Oh, the book is at:
http://www.squeezedbooks.com/book/show/23/the-wisdom-of-crow...
But I haven't finished the summary yet... contributions welcome:-)