Great advice from Woodstock.
Each social network has its own 'community thing' going on, which can be hard to define from your first view visits. Get this wrong and you will find yourself posting articles which will never see the light of day, (happened to me on Reddit and Technorati).
Simply publishing articles isn't enough, unless they are of earth-shattering significance and even then, if you publish your own work, it seldom gets picked up and voted (or Dugg) heavily.
Better to spend time initially surfing the respective networks and leaving comments (and links). Find out whats working for the community you are surfing, and choose a network which fits in with your genre or topic.
If you find some material which makes you think "blimey I just got to vote for that", chances are you're in the right place.
Try publishing articles to
PR sites, but don't forget to add links at the bottom of the article, for the networks you are targeting (Digg, StumbleUpon, Propeller etc).
Without a doubt the best way to have your material create a "blizzard" of new traffic is if it gets picked up and posted to a network by a third party.
The trick is of course, how to get third parties looking at your material in the first place.
But get it right, and you can generate so much traffic that it knocks your website offline temporarily - particularly applies to websites built around PHP (the Digg effect).
Good luck
Webhead