Google Penguin is a codename for an algorithm update by Google aimed at reducing webspam. It was first introduced in April 2012 and its primary objective was to demote websites that engaged in spammy and manipulative link-building practices.
The Penguin update targeted the so-called black-hat link-building techniques, including buying links, link farming, automated links, PBNs, and others.
The primary goal of the Penguin update was to reward high-quality websites and enhance the overall quality of search results.
Since 2012, Penguin has received multiple officially announced updates, and in 2016, it was integrated into Google’s core ranking system.
Currently, the Penguin system is real-time, meaning that the list of sites affected by Penguin is no longer periodically refreshed. Moreover, the system mostly works to devalue spammy links instead of demoting websites that use link spam in search results.