Black hat SEO :
It is the technic to rank search engine fast in non-organic way or not ethical. But search engine are enemies of black hat SEO that gives only short term search results. Black Hat meant for search engine only and not visitors. In black hat SEO the visibility lack to human beings.
Let see some of the examples of Black hat SEO.
Hidden Text: - Hidden text is textual content which your visitors can't see but still readable by Search Engine. It can be done by making font color as same as background color or making font color as same as background image.
Keyword Stuffing:- is a technique used to spam search engines by placing excessive or irrelevant keywords in the meta keywords tag or throughout the content of the page. Because search engines scan web pages for the words that are entered into search criteria by the user.
Landing Pages/Doorway Pages/Bridge Pages :- It may be define as the fake pages that the user will never see. Doorway pages are pages packed with keywords, and designed solely for the search engines. It is an attempt to trick search engines into indexing the site higher.
Cloaking:- It is a technique in which the content presented to the search engines is different from that present to the user's browser. This is done by delivering content based on IP address of the user requesting the page. When a user is defined as search engine spider, a server side script delivers a different version of web page. It is use to deceive the search engine. Actually what happens it is a CGI script which reads the IP address of the requester against the IP address of the SE spiders. If no match is found then requester is identified as “human”. The point is that highly optimized web pages are served to SE while human visitors get a different web page from the same url.
Link Farming:- The process of exchanging reciprocal links with websites in order to increase Search Engine Rankings. This is done just to increase the number of sites that links to yours site, but it is consider as SPAM. Because Google says we have to exchange links only with the site that are having relevant theme as same as our site and a link page doesn't contain more then 50 links.
Page Hijacking:- It is the form of spamming the index of search engine. Mostly web hosts do it, when we forget to renew our domain name. It is achieved by creating a rough copy of a popular website which shows content similar to the original website to a web crawler but redirects the web surfers to the unrelated or malicious website. Link spammers monitor DNS records for domains that will expire soon and buy them when they expire and replace the pages with the links to their pages.
Automated Search Engine Submission Software:- We don't have to use such softwares for the promotion purpose. They don't work efficiently and sometime they caused for banning the website. We don't have to rely on them.
Duplicate Content:- To use the same content on different pages, Google consider it as spam and if it detects large amount of duplicate content on different sub or main domains then Google can impose “Duplicate Content Penalty” which results in losing rankings. So we should put different meaningful content at our pages and on sub domains also.
Content Solely For Search Engines:- Don't publish any content that is meant for search engines only. Content rich in keyword density not useful for human beings and it is easily detected by Google and other search engines which results in penalties. Therefore we always have to write content firstly for humans and then for crawlers and robots.
Frames:- Though frames are not “Black Hat SEO” but frames should be avoided as they cause huge problem with crawlers to index the site.
Email Spamming:- Unwanted, unsolicited email, to send the emails to number of people not directly related to SEO is called email spamming.
Hence these are the major Black Hat SEO Techniques. These techniques gives short term results and lead to the banning of site. So we should never implement such techniques.