If you are a freelance article writer or run a website, then plagiarism detection is something you should never neglect. A website is only ranked on top of the SERP if it has original content. Once you list the website on search engine directories, the search engines will detect plagiarism and penalize the site if it has copied content. The penalties depend on the extent of plagiarism. One of the biggest disadvantages of this is that the website will drop in SERP ranking. If a site were on top, it would now be at the bottom due to copied content. It is, therefore, important to detect copied content before you upload it on the website.