Additionally, a great body of work in behavioral psych tells us that humans have a tough time measuring preferences on any absolute scale; however, we can consistently compare two items as better or worse (particularly when they're of the same type, instead of apples versus oranges). "Riffle independence" is a recent method for modeling these kinds of preference distributions, and has been used quite successfully for social curation of the blogosphere - i.e., showing the best set of blogs that span the topic space and have little redundancy.
Additionally, a great body of work in behavioral psych tells us that humans have a tough time measuring preferences on any absolute scale; however, we can consistently compare two items as better or worse (particularly when they're of the same type, instead of apples versus oranges). "Riffle independence" is a recent method for modeling these kinds of preference distributions, and has been used quite successfully for social curation of the blogosphere - i.e., showing the best set of blogs that span the topic space and have little redundancy.