Like everything SEO has its dark side too. Black hat SEO is the name for all SEO practices that are known for being manipulative or unethical, and in the long run can hurt your website, or even get it banned from search engines.

Of course, there’s a very thin line between “perfectly fine” and “unethical” … one day some SEO practices are OK, and the other they are suddenly black hat, so there’s no exact list of such practices.