The Penguin accompanied the Panda in April of 2012 in Google’s algorithm army of programs and filters which has the mission of cleaning up the search engine results, improving accuracy, relevance, and site legitimacy. The Panda update launched by Google in February 2011 was named after the employee who created the filter, but the Penguin got its name in a much different way. A popular online magazine put a poll out to its readers in order to find a suitable name. Apparently Titanic was the leader until an SEO expert Todd Bailey compared the algorithm being used to a penguin’s life cycle and sense of smell (over a month after the program’s launch); the name stuck and the algorithm was dubbed the Penguin.
The Penguin’s purpose is to demote sites that violate the Google Webmaster Guidelines. Sites which have gained ranking by way of black-hat SEO such as, but not limited to, cloaking, keyword stuffing, duplicate content, and link schemes were sought out and demoted by the Penguin algorithm. The biggest difference between the Penguin and the Panda, which share the fundamental purpose of down ranking websites, is that the Panda’s focus is on user experience whereas the Penguin’s focus is on content and unusual linking to gain rank.
The Penguin’s effects on site ranking was smaller than that of the Panda update for the clear reason that the Panda had cleaned house for over eighteen months already. It is reported that the effect for sites which are in languages such as English, German and Chinese was only about 3% and there was an increase in percentage in other languages which have [now] been classified as more likely to be spammy.
Google has taken steps to ensure that people are able to provide feedback on the Penguin program and target two categories of people: those who wish to report spam that was missed, and those who are site owners and feel that the program affected their site in an unfair way and is appealing for an amendment. You can find the reconsideration form through the Google Webmaster Tools page.