I wonder if this is still effective. Even myself don't read articles anymore and I think having a lot of keywords for an article and submit it to articles directories could not help your site. This is only good is someone who found your article will also found your link under it...what do you think?
People who look for getting free content usually read the article for copy editing, moreover I think people are diverted towards blogs these days.
Only post to popular article sites like ezine and goarticles, the only 2 worth posting to, the others are extremely low traffic
I think most people submit articles to build their backlinks to improve their serp over time, I'm not sure how many people actually read articles.