Matt today, answered question about links from relevant content in article directories, being in SEO, I will say it as rare question if someone ask link building from Article Directories, as long time ago these methods was declared as spammy and un-natural.
Though in 2004, articles directories were the favorite methods to game Google for getting links and gaining search engine rankings, rather I will say it was working till the invention of Panda and Penguin algorithms, but not anymore now in these days.
Google’s version of article directory links as explained by Matt is having 300-500 words content, spammed with 2 or 3 rich keyword anchor text links in bio and published on one or more articles directories. Now this is clearly against the Google quality guidelines having links from such directories with same contents being duplicated.
As per Matt, contents in such directories are of low quality and Google does not give much value to these types of links.
Google link schemes quality guidelines already says “Large-scale article marketing or guest posting campaigns with keyword-rich anchor text links” is an un-natural methods.