Socrative

"Founded in 2010 and based in Boston, Socrative offers a real-time student response system that allows teachers to easily create quizzes that to check for student understanding. These quizzes can be taken on a variety of mobile and desktop devices. Ben Berte, Socrative's CEO, tells EdSurge that the company has over 750,000 teacher users around the world, "with 30,000 new teachers signing up each month.""