I have to disagree with that. The point of stumble is to keep stumbling. I asked before I started a stumble exchange blog and they were all for it. They don't rate with votes quite the same way as digg.
Having friends is the ONLY way to come to front page. You can write a great story, but noone is going to even notice it in the flood of other stories. The only way to come out of flood is to have friends digg for you, so that you come to upcoming section. Once there, people will actually notice you and might give you some more diggs. Once on front page the title is the most important. If people like it, they will digg you before they even visit your site.