Black Hat SEO is a disapproved practice that could increase a page's ranking on a search engine result page (SERP). Some commonly used SEO techniques include Keyword Stuffing, Cloaking, Paid Links, Doorway pages, Hidden content & Duplicate Content. If Google catches a site using these methods, the site is penalized. Chicago SEO agencies ensure that they do not utilize such techniques. Read here to know 4 Black Hat SEO Techniques to avoid when marketing content .