Every coin has two sides. Rightly said! Every entity or idea has its pros and cons. Thus no single identity is perfect. When there is a law, there will always be escape ways from the clutches of law. The experts of any field know how to manipulate that field and get the most out of it. Similarly with growing demand of SEO methods, there are various escape ways which require fewer efforts and return good revenues. But these methods are not welcomed by the search engines as they just not aim at the promoting own business, but promoting online business through others sites and in turn might harm the ranking of that particular site.
It is called Black Hat SEO or SEO spamming. This takes place when irrelevant use of any irrelevant methods for pulling the top rank. These applied methods are targeted at manipulating or playing tricks on the search engines. These methods end up fetching poor quality and many time irrelevant results. These methods involve in creating large number of web pages which are actually very much sub standard and have very poor quality content. Such content cannot get consistent and good result. Such kind of pages or sites gets poor quality search results. Web pages created using this technology can easily pull top ranking in the search engine result but can easily crash on viewing. These web pages attract various irrelevant links to their site, just to increase the link exchange rate. But these links may not necessarily be related to the content or services of the company. Such sites can easily climb the ladder of success of being one of the top sites within a short span of time. But once these tricks are detected by the search engines then, these sites are banned for viewing or removed from the online directory maintained by the search engines.
There are some rules set by the top search engines for getting profits using the environment provided for the online business. These ethics are expected to be followed strictly in context to mutually benefit each other. Some of the companies fall prey under trap of agencies offering cheap services for higher ranking and more benefits, due to their ignorance. They may get good results instantly but may face the music later, once the site is banned. Some of the companies who do not wish to sustain longer, deliberately apply these methods for a short term goal being visible and collect as much benefit as possible during this short stunt.