What is duplicate content?
The duplicate content is a problem that all search engines face.
They cannot afford to keep multiple copies of the same content on their servers. Millions of web pages are published every day, they must preserve their resources at all costs by managing optimally their storage as well as their computing capacity.
Overall, we define a situation as a duplication of content when a search engine indexes many times the same text (a part or a complete text) from different URLs.
There are different kinds of duplications, ranging from the complete or partial copy of a page from a website to another, to the self-duplication of content (on the same website) which is very common.
The near duplicate is also the subject of specific attentiveness.
The search engine will have no interest in offering their users various identical or very similar results. They would rather diversify their offers of relevant contents.