This is usually because Google and other search engines as well hate duplicate content and hence rank them very low, this is because they aim to deliver to their visitors the most original results hence if your content is unique and original you will rank very fast and you will start receiving organic website traffic from Google and other search engines like Bing, Yandex, Duck duck go and others. Search engines have their own algorithms which they use to determine which content was originally published first and hence give this first publish a priority after all the others that were published after this.
So, if you need me to write content and articles for your blog, i will willingly do this job and i promise to deliver a great deal of the most original unique content that will pass copyscape and plagiarism checker link to 100% and no duplicate will be of the content on the internet hence those that will come after this will be considered as duplicates and yours will be first. I promise you the highest quality and you can tell me any topic you wish for the article and i will do all keyword research and make sure everything is absolutely perfect and when i deliver each and every article, it will be ready for publishing.
