Using Digg to index a new page?

I'm a little confused about how to go about getting search engine credit for original content. Lately, when I add a new article to my site I make sure I get the new page indexed before publishing it elsewhere, like on EZA.

For a while I submitted my new page to Digg to get it indexed quickly on Google. This worked well the first couple times but after that I started noticing that only Digg's url showed up in the listings and it took several days for my page to show up, even though I also ping it and resubmit my xml sitemap to Google.

This time I decided to make sure Google sees the content on my site first. So I have not submitted it to Digg or other bookmarking sites. Two days ago I uploaded the new page, submitted a new xml sitemap to Google and pinged the page. Still not indexed.

What am I doing wrong? Or am I just too impatient?

I've read recently that even after submitted a sitemap you will not get a page indexed unless it has external links pointing to it. So should I go back to using Digg for this purpose? And will this give me original content?

Thanks for any advice.