If you want your Diggs to be Digged by more people, don't forget to SHOUT about it, not only in Twitter or other social networks, but in Digg too.
How to send shouts to your friends:
Go to your profile, click on one of your diggs. You should now see the Share-symbol under it, right beside the favorite star (which also is a good thing to tick!), click on it and choose which friends to send it too.
Make sure you can get shouts from your Digg friends:
Click My Profile ->Settings -> Shouts & Photos and change the "Allow shouts to me from..." tick box as pleased. (I recommend to set it to: My friends)
That way you to get more use of your digg account.