Black hat SEO techniques include:
• Keyword stuffing – put lots and lots of keywords on site without real unique content; also hiding keywords on site and make them visible only to search engines,
• Doorway pages – single pages to direct traffic to other pages, do not have any valuable content itself,
• Cloaking – showing one version of site to the users and another to the search engines,
White hats vs Black hats
White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing – Wikipedia.
White hat SEO specialists create websites for human beings, make them easily accessible for search engines and use other methods to promote them on the Internet.
Black hat SEO’s create website only for search engines. They break search engine guidelines and use deception to drive traffic to a site with low value to the user.
White hat SEO aim to stay in high rankings for a long time, generating targeted traffic to the site, satisfy incoming users by giving them what they search for and enable search engines to crawl their site with ease.
Black hat SEO aim to trick visitors to visit a website, trick search engines by showing it a different (SE optimized version of a site) and rank well for desired keyword for short period of time. That is, until search engine discovers an unethical method used by such site and removes it from search engine results for those keywords.
Conclusion
Don’t do evil. Make websites for people and don’t deceive or trick them. Don’t do black hat SEO.

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