There are way more things contributing to what gets on the front page on Digg. The algo looks at how many diverse ppl are digging this story, meaning ppl who do not digg the same type of story all the time. How fast the number of Diggs is accumulated. How long a user has been registered and what their activity is like, do they only submit and not Digg/Comment. There is even more that the algo looks at, but it is not just Diggs that count.
