We use article marketing as one piece of the
SEO campaign for many of our clients and while they're certainly not the best thing in the world as far as
SEO goes, they certainly drive traffic to the sites and encourage bookmarking and organic links from blogs, etc. when people find the articles on the article sites.
Set up a Google Alert to notify you of someone using snippets of your article, and if alerted, submit the offending site to their DMCA department. It's that easy. Ignoring article marketing completely because you're worried about a duplicate content penalty is just silly.