Black Hat SEO or Spamdexing is a type of SEO (search engine optimization) and is the process of using the different technique, SEO strategies and other tactics aggressively so that the website can enjoy a better ranking with the search engine. In this type of SEO, the person is concerned about SEO only and may not consider whether the information given on the page is relevant to the users or not. The page may be over stuffed with SEO keywords and may invisible text that can be read by the crawler. This kind SEO is not made according to the search engine’s guidelines and is only focused on SEO.
Using Black Hat SEO for getting quick financial return is not considered to be ethical and may actually get your website banned by the search engine. It is best to avoid this kind of SEO practice as it is fruitful in the long run. It is generally used by people who just need to get high financial returns and are not affected by being banned from the Search engines. Thus this kind of SEO is considered by sites which are looking for short term gains and they use keyword stuffing in the webpage to appear in the search engine’s result.