Top 10 users contributed 1792 of the frontpage stories - i.e 29.8%It appears Digg is run by a very small community, just a couple hundred users. In this sense, it may be similar to the much older Kuro5hin.
Top 100 contributed 3324 stories i.e 55.28%
There are 444,809 registered users, out of these only 2287 contributed one or more story for the period of 6/19/2006 9:31:28 PM to 7/30/2006 4:41:34 PM
Update: The Duggtrends article is up now.