Duplicate Content
A Recent Reason for Dropping Rankings
There are only so many ways to describe "Porcelain Veneers", so who cares if my website's content is the same as another website?
Why Not Use Duplicate Content?
Often, when starting a website, the owner of the website will opt for generic content as this text is usually worded well and far easier to work with than creating the website from scratch. Or in an effort to gain better search engine results content is stolen from well ranking sites with the belief that this will help in obtaining superior position. Both of these thoughts are incorrect when search engine optimization is concerned.
Without even getting into the moral and copyright issues of plagiarization, duplicate content is something to be avoided at all costs; if for no other reason than to rank well with these search engines. It is because of the above reasons that Google, Yahoo and the other engines have started actively scanning for duplicate content. From all appearances they are thus far looking for duplicate paragraphs, but as they acquire greater computational resources even duplicate sentences will be scanned for.
Every Rule Has an Exception
Of course not everything can be unique. For instance, submission forms, catalogs and shopping carts should follow a standardized wording and layout to provide a user friendly experience. The search engines are looking for content and these types of pages are not there for that purpose, so consider these as a legitimate exception.
How to Correct the Issue
In the past Google in particular would black list sites that it felt were intentionally breaking their rules. Where this is still a consideration, Google has softened with time as to how strongly they deal with what they consider an issue. In most cases simply updating a site's content is enough to correct any negative ranking that is applied to your site.
Can I Protect My Site's Content from being stolen?
In a word; no. Many people have gone to great lengths to prevent the duplication of copyrighted material, but in the end nothing has worked. Look at the Motion Picture and Music industries and note their failing approaches to illegally distributed material. The best practice is to not put anything on your website that you do not want stolen. Especially if your content stands out as brilliant. Be sure to include a copyright on each page of your site and wait for your content to appear elsewhere.