Article submission is a popular way to increase traffic. There are a lot sites that allows article submission. There is a strong competition between these sites. From my experiences i think webpronews is one of the best sites to submit articles.You can try it.
Any site that lets you post articles is essentially useful. But putting the content on your own site would be the best answer. Unless its a useless article of course...
I have only seen one Backlink in Google for my site from GoArticles! The sites in which the articles are not reviewed are not as good as the ones like Ezine!