Hartz started Eventbrite, an online ticketing platform, with her now-husband Kevin in 2006. Since its founding, the company has raised $140 million from firms like Sequoia Capital and Tiger Global Management and reached $2 billion in gross ticket sales this September. Entrepreneurship forced Hartz to appreciate candid and collaborative conversations. "I had to learn how to ask for help," she says. "Everyone always thinks it's brave to go out alone, but I think it's even braver to put yourself out there in front of others, and to figure out how to work together."