How the smartphone can become a personal concierge (not a stalker) in the mobile marketing revolution of smarter companies, value-seeking consumers, and curated offers. Consumers create a data trail by tapping their phones; businesses can tap into this trail to harness the power of the more than three trillion dollar mobile economy. According to Anindya Ghose, a global authority on the mobile economy, this two-way exchange can benefit both customers and businesses. In Tap, Ghose welcomes us to the mobile economy of smartphones, smarter companies, and value-seeking consumers. Drawing on his extensive research in the United States, Europe, and Asia, and on a variety of real-world examples from companies including Alibaba, China Mobile, Coke, Facebook, SK Telecom, Telefonica, and Travelocity, Ghose describes some intriguingly contradictory consumer behavior: people seek spontaneity, but they are predictable; they find advertising annoying, but they fear missing out; they value their privacy, but they increasingly use personal data as currency. When mobile advertising is done well, Ghose argues, the smartphone plays the role of a personal concierge–a butler, not a stalker.