In order to prevent fraud, Digg is making some changes to how stories can be promoted on their Website.
“While we don’t disclose exactly how story promotion works (to prevent gaming the system), I can say that a key update is coming soon. This algorithm update will look at the unique digging diversity of the individuals digging the story. Users that follow a gaming pattern will have less promotion weight. This doesn’t mean that the story won’t be promoted, it just means that a more diverse pool of individuals will be need to deem the story homepage-worthy.”
Some commentary on why Digg is rigged.
Sites like Digg have become huge traffic drivers to Websites it links to, making them a key player for online marketing.