Slate has an interesting article titled "Digg, Wikipedia and the Myth of Web 2.0 Democracy" [1] in which the author, Chris Wilson, talks about how a few people are responsible for most of the entries in Digg [2] and Wikipedia [3] and various permutations of having an open-access site.  He makes that point that  "Despite the fairy tales about the participatory culture of Web 2.0, direct democracy isn't feasible at the scale on which these sites operate. Still, it's curious to note that these sites seem to have the hierarchical structure of the old-guard institutions they've sought to supplant."