What is Google Penguin
 

Another algorithm update from Google that gave SEO experts another blow was Penguin that was launched in April 2012. The idea underlying the update was simple enough- penalize and decrease the rankings of sites that breach Google’s Webmaster Guidelines set the by the search engine.

This included lowering the search engine rankings of all those sites that practice black-hat SEO techniques like duplicate content, keyword stuffing and cloaking to name a few.