BUT: External duplicate content also exists due to someone else's fault! It is caused by plagiarism or content theft.

[Shishirgano9]

Printer-friendly pages and PDF downloads generate their own URLs.
Also variations of pages of a product, links, tags
Distinguishable session IDs receive their own web addresses.
Content management systems add URL endings with /index.htm/ or similar.
Causes of external duplicate content
External duplicate content means that the same content appears on different domains. If it is your own fault, it is almost always an oversight . For example, if a company runs its projects on different domains or publishes a message on both sites.


Your own content suddenly and unexpectedly nurse database appears on other people’s websites.
The original and copied content are indexed.
Search algorithms do not recognize the original.
Therefore, only active action can help against external duplicate content.
SEO tips for finding and avoiding duplicate content
Basic tip:
Duplicate content is irritating. This should be avoided.
Strategic SEO therefore begins with your own website and the various options available to strategically present your own products and strengths.
Arrange the best stage for your services. A strategic overview of your website also often reveals sources of duplication in the content.

Ensure the best performance: Read 10 tips for an optimized web presence.

Find duplicate content:
Tip 1: Basically, the Google Search Engine can be a good way to detect duplicate content. Excluded websites can be shown under Coverage in the Index menu . In the details you can then see Google's classification and reasoning.