Black hat SEO is search engine optimization (SEO) that uses less than legitimate techniques to achieve results. There are two kinds of search engine optimization, white hat and black hat. White hat SEO is where rules are followed and approved techniques are used to improve a website search ranking. Black hat is where someone cheats to get the same result. Many techniques that are now considered black hat SEO used to be widely used and perfectly legitimate. Some people abused these methods and caused problems for others on the Internet. This meant the methods were quickly disapproved of by search engines and frowned upon by the SEO community.