Black hat search engine optimization is the opposite of White Hat SEO, these Search Engine Optimization tactics are ways to get better rankings for a website by tricking the Search Engines guidelines. If not immediately, using black hat SEO practices that can hurt your website in the long run or even get it banned from search engines.
These black hat SEO tactics should not be exercised: Content Automation, Doorway Pages, Hidden Text or Links, Keyword Stuffing, reporting a Competitor, Cloaking, Link Schemes (including buying links, Link Farms, Link Networks, etc.), Article Spinning, Automated Queries to Google, duplicate content and more.