Black Hat - a term taken from the slang of English-speaking computer security specialists. They refer to hackers who commit cyberattacks, guided either by a desire for profit, or just idle interest.
In SEO, Black hat is a synonym for black optimization, i.e., methods of website promotion that are either not approved by the search engines or are explicitly prohibited by them.
The use of black optimization methods can, on the one hand, significantly increase the speed of promotion for highly competitive queries, and on the other hand, it will inevitably entail sanctions from the search engine. The only question is how soon they will be applied.
We can distinguish the following main methods of black hat SEO currently used: cheating behavioral factors and hiding text.
By cheating behavioral factors, we mean software simulation of the actions of real visitors who come to the site for certain queries, spend a significant amount of time on it and complete the visit with a targeted action (purchase, etc.). However, if the search engine can not distinguish the program from real people, the site can get high positions in the search results as popular with visitors.
Hiding the content means that the landing page contains text inaccessible to the user, rich in keywords, and therefore unattractive to the user. There are various ways to make text invisible to the user. For example, you can place it under a drop-down link or overlay an image that disappears when you click on it.