Ghose's book "Tap" discusses how businesses can benefit from consumer data collected through smartphones and how the mobile economy has grown to over three trillion dollars. He describes contradictory consumer behaviors like seeking spontaneity but also predictability. Ghose identifies nine forces that shape consumer mobile behavior, such as time, location, and weather. The book highlights how mobile influences shopping and argues that advertising can work well if done respectfully, acting as a personal concierge rather than stalker.