crowd to help design the cars themselves. they have a community of 50,000 people out there every day working on how to design the cars, what the engine should look like and the wheels. by the time they are ready for sale, they have a huge group of people invested in that outcome. >> how do you build that community in the first place? everyone talks about you have to be authentic, not ask people to buy, but have a conversation. i can tell you all the tips on building a relationship with your users. it is hard. >> it is. we used this term in the book, how do you structure pull participation. if you want to build a community, it's about creating the right incentives to participate. they call this drawing the box tightly around a challenge. they really, carefully think, what can the crowd do for us? what's going to be gratifying for people to be involved in? it is carefully designed.