Quizlet is an online learning tool created by Andrew Sutherland. It was originally conceived in October 2005 and released to the public in January 2007. As of November 2015, Quizlet has over 100 million user-generated flashcard sets and more than 40 million monthly visitors . It now ranks among the top 50 websites in the U.S. In 2016, Quizlet was recognized by SimilarWeb as the fastest growing US Education site in 2015.