Duplicate Content Algorithm
Duplicate content is a big problem for Google, so they use an algorithm to compare your page content with the pages of every site that is in their index. If you have the same words in the same order as an older page they you are considered to have ‘scraped’ that content (a common practice amongst low quality spam article sites).
The result of being considered to have duplicate content is that your page will drop in SERP’s and if you have several pages then you run the risk that your whole site will be flagged as low quality and you will be de-indexed.
What is Duplicate Content?
For more information about the different types of duplicate content see here. Each page needs to be 100% unique to be completely safe from incurring a ranking penalty going forwards, however, there are currently sites with only 80 – 90% unique content.
Our belief is that this is a dangerous strategy. Google is continually refining and honing its ranking criteria for each site. It is very rare that it ever loosens the criteria required and historically only ever increases the quality of criteria.
Why Do You Need Unique Content?
Unique content is a strong indication to Google that you have written text specifically for the page. Google doesn’t want you to copy other information, it would rather you link to any content that you want to reference, which helps everyone. For this reason, instead of copying any existing text that you want to include, create a link to it that opens in a new page.
When you create new content, check it is unique using www.copyscape.com which will show you what content is duplicate, as well as showing all sites that share the same text.