Copying of contents has been the greatest headache for most of the genuine websites who bring up their own original and unique materials only to find to their dismay that they are considered to be duplicate.  The reason is that without their knowing some unscrupulous trader on the website have copied the contents and floated them in such cunning manner that they look as the genuine ones. 

That is why some of the websites and search engines continuously verify the web to find out such cases of plagiarism especially when some contents are placed with them for search engine optimization.  They consider removing such violations as part of their genuine job required for improving the search engine ranking.

If you desire to know whether your contents are being copied you can follow a method.  The method would be to take out random parts of your contents and search the web for their duplicates.  This can be done with Google, Yahoo or most search engines. Many other automatic software solutions have come up. 

If you find some copyright violation you need not be worried since you have various options.  You can file notices of copyright or trademark violations under the Digital Millennium Copyright Act or DMCA and similar other legal provisions like the Copyrights Acts. 

These Acts are prevalent in almost all countries today.  People who indulge in violation of copyrights for search engine marketing should think twice before they indulge into such illegal activities.