The SEO of your website is, of course, of utmost importance. It is what dictates the amount of traffic the website receives, which 
will directly impact the success of the website, in many ways. For this reason, it is very worrying for website owners when they see a drop, of any sort, in traffic or search ranking. What could have caused this? It is important to find the root cause of the problem so you can rectify it, in order to limit the damage it can cause to the organic health of your website. Here are some common reasons behind drops in SEO.
Is the data behind the SEO drop Correct?
The first step is to make sure you really have a problem on your hands. You need to be 100% sure the problem exists before you can dive into the potential reasons behind the problem. Use Google Webmasters, in combination with Google Analytics, at the minimum, to decipher the statistics behind your website.
Plagiarism
Plagiarism and copying content is punished severely by search engines. If there is one rule Google had to tell website owners, it would be to create unique content only.
If your website is caught copying content, even if it is just a paragraph etc., then be expected to get severely punished, both in terms of the article traffic and your website as a whole. Use tools such as CopyScape to go through your content, to make sure it is not copying from other sources.
Copyright case
If your content is not copied, but there is a legal matter with the content, this can cause drops in SEO too. For example, if your content contains confidential NDA information and there is an open case against it, then Google are very likely to reduce the ranking, if not eradicate it altogether, to protect the party that made a claim against the content.
Duplicate content
Similar to plagiarism, having duplicated content on your website will make it harder for Google to determine what article to point to their search results. It reduces the quality of the content if it is not unique, reducing the ranking it will achieve organically.
Spam comments/links reduces SEO
It is very important to make sure that your comments and links are moderate. Any sort of spam that reaches onto content, be it a comment on an article, a link into the content or a link into the comments, has the potential to reduce the SEO of the content. This is because search engines uses the comments as a factor to determine how good the content is. If there are lots of conversational and interesting comments, this will add to the SEO of the content. If they are all spam and with links, then it will work in a negative way.
