One thing I learned in this past month on my SEO campaign trying to get a descent traffic I included Digg as one of them and the result are not very good and the material I submitted dint please the Digg Mods. That's fine and I guess you can't please them all. What I found out though that even though I got maybe less than 3 visitors from my Digg submission, Digg now has rank on top in the SE for the Title that I submitted and actually place my site lower. What does this mean is since Digg is a thousand times more powerful than my site, it will rank much higher than me, thus it will actually take traffic from me. That page that Digg created for my posting has no contents of any of my posting nor does it have any link to my site, basically I had just brought Digg a couple of traffic by submitting keywords for it. The moral to this story is,..Don't Digg unless you think digg can bring you traffic. Forget digg as it wont do you no good and in fact it might be a waste of time to you which benefits them with little to no return to you.
I have to disagree. 15% of my traffic comes from sites like Digg, and Digg being the most popular, gets the biggest chunk.
Your content must be worth digging which will indeed bring you lots of traffic, but for most sites the case is not worth the time. An example of the site I submitted is right next to my avatar blog post, tell me if any of the post are of spam. My opinion it deserve more than two visitors.
For me - Digg gets indexed higher than my client's sites - then drops like a rock in a day or two. I love though - how it gets indexed in about an hour.