The other part of the problem is that many websites will be using your digg article verbatim on their website, so generally if Joe’s website has a better page rank than yours and he puts up your article your article now gets to be moved into next rung on Google (and so on) unless most of the people actually refer to your website as the source of the story (backlinks are very important to Google’s Page Ranking).
It’s simple just digg every story no matter how interesting to the Digg crowd. May be that story was not sentilating enough for the digg crowd but it was completely useful to people doing searches on Google. The idea here is not to get an overwhelming amount of traffic but to let the flame burn for a long time over multiple stories. The point is to let your articles stand on its own.