Digg founder Kevin Rose said today that the site will be making changes to its ranking algorithms. The problem is that a small number of Digg users have too much influence over what makes it to the home page. The general perception is that sites like Digg work via the wisdom of crowds, a term recently repopularized by James Surowiecki in his book of the same name. The idea behind crowd wisdom is that large numbers of people with different perspectives will be consistently better than individuals at problem solving. In Digg's case, the problem to be solved is the promotion of stories.
Most people assume that because a large number of diverse people promote stories on Digg, then the resulting top stories are the product of collective wisdom. Unfortunately, Digg doesn't really work that way because each user has foreknowledge of other users' diggs. Diggers promote stories that have already been promoted. This is the herding instinct. If you read Surowiecki's book carefully, you'll note the wisdom of crowds relies on diversity, local knowledge and independence. It's that last quality Digg users don't have. Instead, each digg is an individually applied discrete unit of imitation, leading to an information cascade. It's one big Web 2.0 bandwagon.