matt cutts has said that he personally doesnt like article directories but he never gave an official google stance. theres a youtube video out there on this.
the idea behind article directories is to get other webmasters to use your article where it has a link in it. you also get a backlink to your site. nodollow/dofoll is on the article dirctories page which has your article on it. of course you do not want a nofollow on your site link in the article.
you are basically creating link bait to spread across the web. however, if you use someone's ezine article, you may get screwed with a duplicate content penalty if google cant figure out the author box. this likely one reason to use the rel author tags and have a google plus account for validation.