Black hat SEO is a set of unethical strategies which are used to gain higher positions in search engine rankings. They are called black hat because they are considered to be unethical or plain illegal by most search engines and the SEO community on the whole. These techniques evolved over a period of time as SEO experts were trying to generate faster results. As a matter of fact, most of these strategies were acceptable and ethical at a point of time. But then some people started to go over the board with it and search results started to get affected. So search engines started penalizing websites utilizing these strategies. 

What are black hat SEO strategies and how do we differentiate them from white hat SEO? 

Black hat SEO techniques are used to gain much faster results and may actually work for a short period of time. Some websites have skyrocketed to the top of Google SERPS (Search engine results pages) within as less as a week of using these techniques. But do not be surprised at all if your website is banned for as many as three years by Google if it is detected that you are using these techniques. 

Here are some BLACK hat SEO techniques commonly used by shady SEO experts. 

• Keyword Stuffing: A huge list of the most searched keywords on a particular subject is created and then the webpage is stuffed with those keywords with not even a comma to separate them. A web user is usually shocked at reaching such a page that is stuffed with keywords and unwanted advertisements. The page is totally irrelevant and contains no useful information that the web user was looking for in the first place.
• Invisible text: Once again, the keywords are stuffed on the webpage. However, this time the color of the keywords and the page background is matched so that it can be hidden from users but attracts search engine spiders. For example, a webpage with a white background will have keyword phrases in white so that they are invisible.
• Doorway Pages: This is once again something that the end user will never see. It is a fake page that is created with the sole aim of tricking search engines into listing the website higher.  

I have noticed that the maximum number of webmasters who use black hat SEO or fall prey to unscrupulous SEO experts who promise them instant glory in SERPS, are people who are on a tight budget. However, before you hire any such SEO company, take a moment to think about the risk. Is it worth it? Always make a wise and informed decision.