Pooja Sankar knows very well how it feels to be too uncomfortable to ask a question in the middle of class. As one of the only women in her class at the Indian Institute of Technology, Sankar not only felt out of place because of her gender, she was restricted by social norms that prevented her from looking a boy directly in the eye. So while the men in her class turned to each other for help with questions, Sankar struggled on her own.

It wasn't until the computer scientist landed a job at Facebook in 2008 that Sankar realized she wasn't alone. She met women from prominent computer science programs in the U.S. who had trouble asking questions among their peers — not because social norms prevented it, but because the women didn't want their male peers to think they didn't understand the material.

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Sankar decided to use her skills to solve this issue. She quit her job at Facebook, maxxed out her savings, and built Piazza, an online platform where students can ask questions of professors, teaching assistants and other students.

At first, business was slow. Students asked just 12 questions in Piazza's first four months. But then Sankar realized that by requiring students to log in with their real names, many would still be reluctant to ask questions. She moved to an anonymous platform, and the popularity of the app skyrocketed. By the next quarter, students and teachers were asking and answering questions at a rate of about 50 per week.

Sankar was nervous that allowing people to ask questions anonymously would bring out the trolls, but so far that hasn't happened. Today, there are roughly 1 million users on Piazza and only a few have ever had to be removed for inappropriate posts.

Sankar told Tech Crunch that Piazza is being used by more than 75 percent of the undergraduate students at Stanford, MIT, Cornell, Princeton and Harvard. "It is the way that they connect with the rest of their class, their TAs, their professors and learn together," said Sankar.

And that kind of collaboration makes the whole network stronger.