Proving your right on a certain article as an original writer is somewhat difficult when the same article is already published on another site. Google has introduced unique way to claim your authorship.
If you are the original writer of that article, you can always do what is known as a Digital Millennium Copyright Act notice, where you send in this DMCA request, and you can find the information at google.com/DMCA.html. Moreover, what you are saying is the other site copied you, but you are the original author. So, this site can either counter-notify, which means they dispute that. They say they wrote this page, which has some penalties to it if they are lying. Alternatively, they cannot dispute it, and the stuff disappears off of the other site. So, if someone is ripping you off, you can always do a DMCA notice. If it is an auto-generated site and they are ripping off or scraping a bunch of people, you can also do a spam report, because that is not a high-quality site; that is not the thing that they want to have within their index.
There are chances that you will find an article on one site before you find it on the other site. Moreover, so it is the case that you try hard to check who the original author of a particular content is? There are ways that people can indicate that they wrote the content. Also, in Google News, it just introduced a couple of new tags- almost as an experiment to see how it works: here is the original author of this content. So there are approaches that it is exploring to figure out if there are other ways to do that. However, at least for the time being, you do have ways that you can take action, from a DMCA request all the way up to a spam report. Choice is definitely yours…!!