Google Penguin is an algorithm that has been introduced by Google in April 2012 to counter the menace of black hat SEO techniques that are being followed by Google webmasters to increase their search engine rankings. Specifically the Penguin update targets those websites that are involved in artificial techniques to manipulate the number of links pointing to their web pages. These include link schemes, link farms and other link building and promotional schemes. Websites that have links pointing to them from sites with irrelevant or unrelated or thin content are also penalized
Penalization involves a manual penalty that is imposed by Google on a website. In such instances webmasters receive an email from Google informing them that a penalty has been imposed on them as their website violates guidelines prescribed by Google. Google stops indexing such websites and as a result such websites do not appear high in search results. Google also informs webmasters of the steps that they need to take for removal of the penalty.