Black Hat promotion is mainly defined by means and techniques used when a site is promoted in a manner that breaks the rules of the search engines.
The Black Hat techniques create a very unpleasant experience for the people visiting your site presenting a visual or non-visual content irrelevant for the search engine spiders.
All the methods considered today as being Black Hat SEO used to be promotion methods allowed by the search engines. Being abused and winged by a large number of webmasters they triggered the attention of the search engines and were labeled as Black Hat. The techniques give results in a short term period, but the large majority of sites using them get red flagged and are removed from the search. So if you are considering long-term promotion, do not go for Black Hat.
The most frequently used black hat techniques are mainly those responsible for SEO overkill. Keyword stuffing, invisible text and doorway pages are all part of Black Hat SEO.
Scripts able to make automatic submissions to web directories, backlinks created via auto postings, links flooding the web without a specific target or related content, are Black Hat SEO too.
Of course, many webmasters considered link farms and mininets complex methods and maybe for a week or two the methods show results. However, the SEO forums are filled with people wondering why Google brought down their ranking overnight when they feel they didn’t do anything wrong.
Promoting a website using Black Hat techniques may sound mighty tempting because these little tricks work for a short term and give results in the site’s positioning. Recently, the search engines have evolved in the tracking of such unorthodox activity. The penalty can include removing the site from the search results permanently. The damage is sometimes beyond repair, and that’s why it’s wise to be a patient webmaster and go for steady natural growth.