I have also heard that digg will ban you if you continually only submit an article from the same domain name. so resubmitting the same article multiple times would probably get you banned.
I tried posting something at Digg.com twice but I got ZERO traffic from it. I am wondering how can it be when people are getting thousands of uniques from their Digg posting.
I always stumble my sites when I first get them up and running and most of them receive 300-500 uniques within the first few hours. Then traffic drops like a rock but google finds it almost immediately. 2 birds with one stone...