I have also been the victim of plaigerism, and it is indeed both shocking and maddening. I had written an article called "The Rhetoric of
SEO," and so whereas I had been checking for my article pick-ups by searching on my name, I decided one day to search on the title. In going through the SERP, I came upon a forum where a forum moderator, no less, had posted my article, complete with title in place, and no hint of my name as author anywhere.
I immediately did two things, I posted my own very direct comment to the forum thread, and then wrote the moderator an also very direct note. Within an hour my article was removed, as was my post. I never did receive an email in response. Surprise, surprise. In retrospect, I was lucky to find the article, and lucky that it was removed pronto.
Okay, well, in pondering this miserable practice, and I underdstand the web is rife with it, I think there are several things we can do to monitor use of our text. First, we should perform a weekly check of the search engines, using the title of the article, as well as a unique text string, both in quotes of course. The next thing is to always, always, always put the copyright symbol, the date (month and year is standard practice in print, but with the pace of the web, the actual date of article completion will register you as the indisputable writer.) Follow the date with your name or the name of your company/organization, whoever owns the copyright. By placing the copyright statement on the text/site, you are officially "registering" your work, giving you inarguable ownership.