For search marketers like myself, knowing the dates and implications of  Google’s algorithm updates can help explain changes in rankings and organic traffic. Google changes its search engine algorithm around 500–600 times each year. While most of these changes are minor, every few months Google rolls out a “major” algorithmic update that affects search results in significant ways. Understanding the updates to the algorithm can help increase the effectiveness of your search engine optimization efforts. Visit Moz’s Google Algorithm Change History for a more details around each update.