One of social bookmarking site I use to distribute my articles and sites is the Stumble Upon. This is my usual routine when I made an article, submit to ping site, yahoo buzz, digg, plurks, twitter and stumble upon.
I consider this process as one of my search engine optimization or SEO. I get good traffic from this bookmarking site due to many users and people use Stumble Upon when engaging in the internet. Plus the traffic I get from Stumble is increasing as time goes by and I do not need to update or submit my articles.
Bookmark this site now so you will never forget stumbling on this!