Ghose's book "Tap" discusses how businesses can benefit from consumer data collected through smartphones and how mobile technology is shaping consumer behavior and the economy. Drawing on research from around the world, Ghose describes contradictory behaviors like seeking spontaneity but predictability, and valuing privacy but using personal data as currency. He identifies nine forces, like time and weather, that influence consumer actions and examines how companies can understand these forces to improve mobile advertising and engage customers as personal concierges rather than stalkers. The book explores the growing power of mobile and opportunities in an increasingly digital world.