Lets say you have a blog post you want to promote.
1 Make a research before, and find two good searched long keywords appropriate to your blog post story.(if you want your traffic to convert)
2 Go to digg and submit your post and in the title put your first long keyword and in the description your other l. keyword
3.Thats it.No need to share your story with friends (even this is better for long term and to reciev traffic from digg to).
Afther one hour search you keyword and you should see it in the first page of google (if it's a competitiv long keyword probably on second page, or third)
You should see in your g analytics traffic from digg but basicly is from google