Sheryl Sandberg admits she was terrified to step onto the TED stage in 2010 -- because she was going to talk, for the first time, about the lonely experience of being a woman in the top tiers of business. Millions of views (and a best-selling book) later, the Facebook COO talks with the woman who pushed her to give that first talk, Pat Mitchell. Sandberg opens up about the reaction to her idea, and explores the ways that women still struggle with success.