Black hat seo is a UN ethical to search engine, it’s to break the search engine rules and regulation, but easily promote your website. You accept success with your way... GO with your way. Clearly Google accept not address HOW TO optimize your website
yes man, blackhat seo is the illegal method that most webmasters use it to gain quick and high authority in their niche but it does not stay permanent as they will get catched and banned someday.
When selecting an SEO agency it is important to review how they balance ethical SEO with the need to maximise search rankings, particularly for competitive keyphrases, through exploiting understanding of how the search engine ranks position. Some commentators talk about black-hat and white-hat SEO, but unfortunately it is nowhere near as a simple as that. This post looks at a great source to discuss and define Black-hat SEO.