A Google Penalty is the negative effect on a site’s search positions based on updates to Google’s search algorithms and manual inspection. Google penalizes sites for engaging in practices which are contrary to its webmaster guidelines. These sanctions may be caused by a manual inspection or algorithm upgrades like Google Penguin.
Google Penalty can lead to the drop of positions for each page of a website, for a particular phrase, or for a particular page. Any drop in positions brings with it a significant drop in visitors for the website. To discover if a Google penalty has influenced a domain, site owners can use Search Console and analyze the timing of the traffic fall with the time of known Google upgrades.