Duplicate Content is a common term that refers to the same or almost same content in different websites pages on the internet.
In fact when search engines crawlers meet almost same content they will not feel happy and they will try to choose only one of these duplicated contents.
The one they will choose is the most original and unique.
The other contents will be labeled as ´duplicated´ and this will affect badly on the page rank and so the website will not do well in the search engines and traffic will of course decreased.
When the content is considered as Duplicate Content?
For nowadays it is enough to have at least 20% unique content in your pages, i mean if you like an article in another website and want to submit on your own website you should rewrite at least 20% of it to avoid duplicate content situation.
But as search engine(especially Google) are always developing there algorithms i recommend that you reword at least 50% of the original content to keep your rank in the future from being affected.
Duplicate content examples:
1. URL parameters:
Like click tracking or some analytics code.
E.g. When category URL system creates multiple versions of the same page:
In the above case a duplicate content is created by the URL parameter ?color=red.
2. Print friendly:
When multiple versions of the same page get indexed print friendly versions may lead to duplicate content.
The /print/ subcategory will create a duplicate content.
3. Session ID´s:
It happens when each visitor is assigned a different session ID which is stored in the URL.
When you want to use another website article in your website try to do this to avoid duplicate content penalties:
1. Write a unique introduction: The first 50 words, unique means unique, so it is not to rewrite it with just small changes.
2. Rewrite the article: Use your own words to reword the article and give it new look!
3. Add new images and insert them through the text to break it up.
4. Comments from your visitors is very affective to give your article uniqueness so encourage your readers to participate in adding there comments.
After you do all these modifications you need to check if this goes well or not, but how can you know?
You can do this easily by using some of tools or websites (like www.siteliner.com).
Compare your website results by these percentages to know if your page has duplicate content or not:
- More than 69%: Completely different.
- 50 – 69%: Very high level of difference .
- 30 – 49%: High level of difference.
- 20 – 29%: Medium level of difference.
- 10 – 19%: Low level of difference.
- 5 – 9%: Very low level of difference.
- 1 – 5%: Almost the same.
- 0 %: Exactly the same