Later Edit: Unfortunately, this service is now no longer available, as the team decided to suspend their activity. However, we are recommended to try Digg instead.
When you publish articles, you definitely want them to be reached by a wide audience and you try to make them as visible as possible.
But in order to accomplish that, you need to promote your articles using all your resources, including the Social Media and you need to let your readers spread the word more easily. These days, one of the most efficient ways to make yourself heard is Twitter.
Now, there are many things you can do to help your readers popularize your content using Twitter, but, personally, the best choice I made so far was to use the TweetMeme Retweet Button (the button you see on the top right of this article) from TweetMeme.