Black hat SEO refers to the practice of trying to trick the search engines into giving you higher rankings by using unethical tactics, such as buying links. The risk is just too great. Even if you enjoy a temporary boost in rankings due to black hat tactics, it’s likely to be short lived. Google is getting better and better at spotting dirty tricks and sooner or later the progress you made will be wiped out by an algorithm update, or worse, your site will get removed from the index altogether.
Remember when you used to rely solely on search engines for traffic? Remember when you worked on SEO and lived and died by your placement in Google? Were you #1? Assured success. Well, okay, maybe not assured. Success only came if the keywords were relevant to your site users, but it was the only real roadmap to generating site traffic and revenue.