Article directories were once a widely used tactic in SEO and it worked for a short period. Then, as with everything that can help SEO, spammers seized this opportunity and abused it to the point where it is now not advised to be used at all.
Matt Cutts has clarified his position on this with another one of his webmaster videos. The question put to him was:
Links from relevant content in article directories — Seen as good or bad? eg. I link my beauty website from a cosmetic surgery article on say, Ezine? Would you do that?
Not content with a full video about this, Matt also tweeted about this and gave the short answer. No. No you should not use article directories.
Blog Post by: Greg McVey