Using unethical methods to have websites rank higher in search engine results is commonly referred to in the SEO (Search Engine Optimization) industry as "Black Hat SEO". For more information on this topic please refer below listed links:
In short it can be said that black hat techniques are used to cheat the search enigne bots to get higher rankings in the serach engine result page. But with the continuous google algorithm update sites using this black hat techniques are losing their ranking and see their traffic also going down.
I think you want bto know about white hat SEO practices. There are two: white hat and black hat SEO trciks. White hat practices are genuine; these are regeraded by serch engines while black hat practices are disliked by search engines.
Black Hat" search engine optimization is customarily defined as techniques that are used to get higher search rankings in an unethical manner. These black hat SEO techniques usually include one or more of the following characteristics:
* breaks search engine rules and regulations
* creates a poor user experience directly because of the SEO techniques utilized on the Web site
* unethically presents content in a different visual or non-visual way to search engine spiders and search engine users.
It is Black Hat, one of unpreferrable method to search engine optimizers. The things include here is, spamming content, keyword stuffing, using hidden text, try to spoil our competeior reputation and all these type of things comes under Black Hat, it's better don't go to SEO Black Hat, why because now search engines are more intelligent than previous.