New features coming to Digg:
Customizable Alerts
Groups
More here."
"Follow these 3 “simple” steps to get on DIGG front page and rocket your traffic"

Let's begin by explaining why Digg is so important to everyone.
In one word; exposure.
Remember the Save Jericho campaign? It's a prime example. Jericho fans would Digg any Jericho post and the Diggs would number in the thousands.
Once a submission has earned a critical mass of Diggs, it becomes “popular” and jumps to the homepage in its category. If it becomes one of the most popular, it qualifies as a “Top 10”. If a submission doesn't receive enough Diggs within a certain time period, it eventually falls out of the “Upcoming” section.
The system only works when users actively participate on a large scale, so make sure to do your part and Digg content that matters to you!
Basically, the more Diggs an article gets the more people who will see it. I'm not talking about 10, 50, or even 100 Diggs-it often requires thousands. Do you want a network to stand up and notice fans? Do you want more viewers to your blog/website?
The promotion and burying of stories is managed by an algorithm developed by Digg. There is no hard number of Diggs/buries to promote or remove a story. It's based on a sliding scale that takes several factors into consideration, such as number of Diggs, reports, time of day, topic submitted to, Digging/burying diversity, etc.
One of the keys to getting a story promoted is diversity in Digging activity. Until the algorithm gets the diversity it needs of users Digging the story, it will remain in the Upcoming section. That way, the system knows a variety of people will be into the story. This means we all need to digg a variety of topics and not just the few that are only of interest to us.
Here's an article that will explain more.