Duolingo started its private beta on November 30, 2011, and more than 300,000 users joined the waiting list. On June 19, 2012, Duolingo launched for the general public. Due to popular interest, it has received many investments including a $20 million Series C round of investment led by Kleiner Caufield & Byers and a $45 million Series D round of investment led by Google Capital. Currently, Duolingo employs 95 people, of whom many had been working for Google.