Some of the benefits of submitting articles to Article Directories:
The more article directories that a particular article is posted to, the more "backlinks" there are to your own website. Since Google sees backlinks as an indication of an "important" site, your Google ranking will go up and so will your traffic.
The more people who read your article and click back to your main website, the more web site traffic your site receives. Alexa ranks sites based upon web site traffic, so you may benefit that way as well.
