Quizlet has officially reached one billion study sessions completed, has more than 100 million user-created study sets, and is now used in every country in the world.

With its focus on fuelling growth and maintaining this momentum, Quizlet has also raise a #12 million Series A funding, led by Union Square Ventures (USV) and Costanoa Venture Capital with participation from Altos Ventures and Owl Ventures.

The investor group assembled by Quizlet includes venture capital firms known for consumer internet and mobile investing, software as a service (SaaS), education technology, and international expansion, all key aspects of Quizlet's long term plans.

The company says it will use this money to grow the team, expand the product portfolio, build out internationally, and continue achieving its mission to build impactful digital learning tools.

This increasing traction demonstrates the need for learning tools that are learner-focused and curriculum agnostic, according to Quizlet.

Beyond its use by traditional students, Quizlet is used by diplomats preparing for language exams, supermarket employees memorising food codes, and ski instructors preparing for their certifications, the company says.

"Quizlet is the most popular digital learning tool in the world because it is peer-powered and loved by its users," says Andrew Sutherland, Quizlet CTO and founder.

"We're proud that over 40 million people visit Quizlet every month to improve their performance as learners,” he says.

Quizlet continues to expand its product portfolio and today is launching two new products: Long Term Learning and Gravity.

Long Term Learning provides daily study reminders, which automatically learn what students know and increase repetition for what they need to learn and is now available for Quizlet Plus users.

Gravity converts quizzes into an Asteroids-like game to make learning more fun and is available for every Quizlet user on quizlet.com.

"We've added these new features because we believe learning doesn't happen unless it's easy and engaging.

“We have great future products planned and remain deeply committed to every tool helping learners improve their performance. It's an exciting time to be part of Quizlet,” Sutherland says.

Fred Wilson from USV and Greg Sands from Costanoa will join Quizlet's board.

"I look at the education category on iOS and Android regularly to see how our education portfolio companies are doing.

“Every time I do that I see Quizlet at or near the top of that category. I've wanted to be an investor in Quizlet for a long long time, and I'm very pleased that it has come to pass," says Fred Wilson, USV partner and Quizlet board member.

"This investment was about us being able to achieve our mission and make a real impact on education in the world today.

"We're grateful for the support from the Quizlet community so far and plan to only make the experience better," says Sutherland.