Many companies are not aware of the real cost of this type of theft. Not only have companies made a significant investment in content creation, but often that content has been carefully optimized to attract the search engines. If other websites are using your content then your chances of a high ranking are reduced. One way to check for copyright violations is to use the free service at www.copyscape.com.
Here is an example of how to use Google to search for content on your site that other sites have taken: