Karl Ulrich interviews Cory Levy about his startup, After School, the largest social network for teens.

After School is a place for teens who want to be themselves, make new connections, and participate in positive activities--both online and offline. It's a private social network that allows American high school students to share and connect with fellow students at their same school. And millions of students, in more than 80% of U.S. high schools, use After School.

Listen to hear how Cory built After School, and how he knew, after many other entrepreneurial ideas, that this one was a winner.