Google has a long history of famous algorithm updates, search index changes and refreshes.

Google launched the Penguin Update in April 2012 to better catch sites deemed to be spamming its search results, in particular those doing so by buying links or obtaining them through link networks designed primarily to boost Google rankings. When a new Penguin Update is released, sites that have taken action to remove bad links (such as through the Google disavow links tool or to remove spam may regain rankings. New sites not previously caught might get trapped by Penguin. “False positives,” sites that were caught by mistake, may escape.