Black hat SEO is a practice against search engine guidelines, used to get a site ranking higher in search results. These unethical tactics don’t solve for the searcher and often end in a penalty from search engines. Black hat techniques include keyword stuffing, cloaking, and using private link networks.
Cloaking is a search engine optimization (SEO) technique in which the content presented to the search engine spider is different from that presented to the user’s browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page.
Doorway pages are Web pages designed and built specifically to draw search engine visitors to your website. They are standalone pages designed only to act as doorways to your site.
As the name suggests, duplicate content refers to the well-known “copy and paste” content creation practice across domains and means that blocks of copied content from different sources exactly match each other or look very much alike.
This well-known black hat SEO technique is no longer as applicable as it used to be in the past. Now, search engines are too smart to get dodged with this simple trick.
To put this straight, invisible text means implementing white text, a list of keywords, on a white background. This method makes keywords completely invisible to a visitor, but search engines can still detect and index them.