Check out all Google Penguin Update List of all Google Penguin series of on-going algorithm updates over the past few years.Google search engine to improve the value of search query results.
1.Penguin 1.0 on April 24, 2012 (impacting ~3.1% of queries)2.Penguin 1.1 on May 26, 2012 (impacting less than 0.1%)3.Penguin 1.2 on October 5, 2012 (impacting ~0.3% of queries)4.Penguin 2.0 on May 22, 2013 (impacting 2.3% of queries)5.Penguin 2.1 on Oct. 4, 2013 (impacting around 1% of queries)6.Penguin 3.0 on October 17, 2014 (impacting around 1% of queries)7.Penguin...