When there are multiple versions of the same content on the net, search engines like Google may only index the version they think to be the original. This means, you cannot just copy an article and paste it into your blog or some other version of this like poor article spinning, auto RSS Feed re-posting, or some automated scraping program that auto-populates your blog for you from another source.
Other times this can happen is if you syndicate your article and the content is duplicated wherever it is posted. If you do this, it might help if the syndicated article has a backlink to the original post on your site.
This can also occur internally if you have different URLs within your site displaying the same content. If you have multiple versions of similar content, you could consolidate them into one page, use a 301 redirect to the original page or block search engines from indexing duplicate copies. If it appears that you are duplicating content on your site to deceive search engines, your site could be penalized.
If you are re-publishing content from another site, you may want to include a conical tag referencing the original version within the link code. i.e. <link rel=“canonical” href="https://www.owerly.com/originalarticle.html"/>
To check if your content or content that was written for your site is duplicate content, you can paste and run it through Copyscape.com
