You may want to be careful in saying this. It's generally frowned upon for people to compare HN to reddit or Digg without ample justification (which a single duplicate submission isn't).
Understood. The specific aspect of Digg that I am comparing recent trends to is that of submission of duplicate articles, and the inevitable notification thereof by other users.
A small example: http://www.google.com/search?hl=en&q=site:http://news.yc...