Well according to this blog post, digg is a place where some “alliances” of people are responsible for the most of the top stories.
I had heared this before, but never read something with so many proofs on that
What it comes down to is there very literally is a group that controls Digg. If you are within this group and you submit a story, you are more or less guaranteed 10-15 (or more) automatic diggs from this group. What happens to the people who don’t have such a luxury and only get the default single vote like everyone else? This only encourages a cycle where those who are getting votes will continue to get more and more, as they feed each off each other and pat each other on the back.
Check the original post here