Which technique is an example of black hat SEO?

Black hat SEO encompasses any tricks, backhanded words, or manipulative tactics to target pages on a site for higher rankings in the hopes of attracting more traffic. It is considered blackhat because it violates Google's Webmaster Guidelines.   A good example of what this includes would be keyword stuffing; using a keyword too many times on a page so that it pushes the other content out from view. This dark side of Internet marketing is not considered ethical and is actually very easy to detect by search engines themselves which will certainly hurt your site ranking in the long run as well as with users who find themselves being confronted by an all-text page without much actual content.