In SEO, black hat SEO tactics are any aggressive strategies or techniques used for the sole purpose of manipulating search engines into granting favorable ranking results without consideration of the human audience or user experience. Usually these tactics specifically ignore SEO and search engine guidelines. Some common black hat SEO strategies include keyword stuffing, purchasing backlinks, selling backlinks, abuse of rich snippets among others.
It is important to note that black hat SEO tactics can come with severe and sometimes semi-permanent ranking penalties from search engines, especially Google. Make sure your SEO strategy is always following best practices and search engine guidelines – also known as white hat SEO.