What is Black hat and it's techniques ?

Black hat seo is technique in which we use duplicate issues like content,photos, video,hidden links,keyword stuffing doorway pages and many other.It is not good for our site because when Google starts its crawling it considered the site is full of duplicate issues and he penalized the site minimum +30 Google page ranking

                                           Black hat techniques

·                     hidden link

·                     keyword stuffing

·                     doorway pages

·                     incorrect keyword 

·                     link farming 

·                     mirror side

Note:- For Best seo this technique is not good avoid this technique.